Method and apparatus for direct write maskless lithography

ABSTRACT

A method and apparatus to provide a plurality of radiation beams modulated according to at least two sub patterns of a pattern using radiation sources, the radiation sources producing radiation beams of at least two spot sizes such that each of the radiation beams having a same spot size of the at least two spot sizes is used to produce one of the at least two sub patterns, project the plurality of beams onto a substrate, and provide relative motion between the substrate and the plurality of radiation sources, in a scanning direction to expose the substrate. A method and apparatus to provide radiation modulated according to a desired pattern using a plurality of rows of two-dimensional arrays of radiation sources, project the modulated radiation onto a substrate using a projection system, and remove fluid from between the projection system and the substrate using one or more fluid removal units.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the U.S. national phase entry of PCT patentapplication no. PCT/EP2016/081006, which was filed on Dec. 14, 2016,which claims the benefit of priority of U.S. provisional application No.62/273,340, which was filed on Dec. 30, 2015, and U.S. provisionalapplication No. 62/328,475, which was filed on Apr. 27, 2016, each ofwhich is incorporated herein in its entirety by reference.

FIELD

The present disclosure relates to a lithographic apparatus, aprogrammable patterning device, and a device manufacturing method.

BACKGROUND

A lithographic apparatus is a machine that applies a desired patternonto a substrate or part of a substrate. A lithographic apparatus may beused, for example, in the manufacture of integrated circuits (ICs), flatpanel displays, and other devices or structures having fine features. Ina conventional lithographic apparatus, a patterning device, which may bereferred to as a mask or a reticle, may be used to generate a circuitpattern corresponding to an individual layer of the IC, flat paneldisplay, or other device). This pattern may be transferred on (part of)the substrate (e.g. silicon wafer or a glass plate), e.g. via imagingonto a layer of radiation-sensitive material (resist) provided on thesubstrate.

Instead of a circuit pattern, the patterning device may be used togenerate other patterns, for example a color filter pattern, or a matrixof dots. Instead of a conventional mask, the patterning device maycomprise a patterning array that comprises an array of individuallyaddressable elements that generate the circuit or other applicablepattern. An advantage of such a “maskless” system compared to aconventional mask-based system is that the pattern can be providedand/or changed more quickly and for less cost.

Thus, a maskless system includes a programmable patterning device (e.g.,a spatial light modulator, a contrast device, etc.). The programmablepatterning device is programmed (e.g., electronically or optically) toform the desired patterned beam using the array of individuallyaddressable elements. Types of programmable patterning devices includemicro-mirror arrays, liquid crystal display (LCD) arrays, grating lightvalve arrays, and the like.

SUMMARY

It is desirable, for example, to provide a flexible, low-costlithography apparatus that includes a programmable patterning device.

In an embodiment, there is provided a device manufacturing methodcomprising: providing a plurality of beams of radiation modulatedaccording to at least two sub patterns of a pattern using a plurality ofradiation sources, the plurality of radiation sources producingradiation beams of at least two spot sizes such that each of theradiation beams having a same spot size of the at least two spot sizesis used to produce one of the at least two sub patterns; projecting theplurality of beams onto a substrate; and providing relative motionbetween the substrate and the plurality of radiation sources, in ascanning direction to expose the substrate.

In an embodiment, there is provided an exposure apparatus comprising: asubstrate holder constructed to support a substrate; a patterning deviceconfigured to provide a plurality of beams of radiation modulatedaccording to at least two sub patterns of a pattern using a plurality ofradiation sources, the plurality of radiation sources producingradiation beams of at least two spot sizes such that each of theradiation beams having a same spot size of the at least two spot sizesis used to produce one of the at least two sub patterns; a projectionsystem configured to project the plurality of beams onto the substrate;and an actuator configured to provide relative motion between thesubstrate and the plurality of radiation sources, in a scanningdirection to expose the substrate.

In an embodiment, there is provided a device manufacturing methodcomprising: providing radiation modulated according to a desired patternusing a plurality of rows of two-dimensional arrays of radiationsources; projecting the modulated radiation onto a substrate using aprojection system; and removing fluid from between the projection systemand the substrate using one or more fluid removal units.

In an embodiment, there is provided an exposure apparatus comprising: asubstrate holder constructed to support a substrate; a patterning deviceconfigured to provide radiation modulated according to a desiredpattern, the patterning device comprising a plurality of rows oftwo-dimensional arrays of radiation sources; a projection systemconfigured to project the modulated radiation onto a substrate; and oneor more fluid removal units configured to remove a fluid from betweenthe projection system and the substrate.

In an embodiment, there is provided a use of an apparatus or methoddescribed herein in the manufacture of flat panel displays.

In an embodiment, there is provided a use of an apparatus or methoddescribed herein in the manufacture of integrated circuits.

In an embodiment, there is provided a flat panel display manufacturedusing an apparatus or method described herein.

In an embodiment, there is provided an integrated circuit devicemanufactured using an apparatus or method described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated herein and form a partof the specification, illustrate embodiments of an invention and,together with the description, further serve to explain the principlesof embodiments of the invention and to enable a person skilled in thepertinent art to make and use the embodiments.

FIG. 1 depicts a schematic side view of a part of a lithographicapparatus according to an embodiment.

FIG. 2 depicts a schematic top view of a part of a lithographicapparatus according to an embodiment.

FIG. 3 depicts a schematic top view of a part of a lithographicapparatus according to an embodiment.

FIG. 4A and FIG. 4B depict a schematic side view of a part of alithographic apparatus according to an embodiment.

FIG. 5 depicts a schematic top view of a part of a lithographicapparatus according to an embodiment.

FIG. 6 depicts an embodiment of a scheme of transferring a pattern to asubstrate.

FIGS. 7A, 7B, 7C, 7D and 7E are schematic diagrams of a manufacturingmethod according to an embodiment.

FIG. 8A and FIG. 8B depicts an embodiment of a scheme of transferring apattern to a substrate.

FIGS. 9A, 9B, 9C, 9D and 9E are schematic diagrams of a manufacturingmethod according to an embodiment.

FIG. 10 is a graph of a number of lenses versus pitch between adjacentemitters.

FIG. 11 depicts a schematic top view of a plurality of lenses each withan emitter array and a bond pad according to an embodiment.

FIG. 12 depicts a schematic bottom view of an emitter array according toan embodiment.

FIG. 13A depicts a schematic diagram of an emitter array according to anembodiment.

FIG. 13B depicts a schematic diagram of an emitter array according to anembodiment.

FIG. 14 depicts a schematic diagram of a micro-lens array (MLA) moduleaccording to an embodiment.

FIG. 15 depicts a schematic top view of a part of a patterning apparatusaccording to an embodiment.

FIG. 16 depicts a schematic side view of a nanoparticle generatoraccording to an embodiment.

FIG. 17 depicts a schematic top view of a patterning device according toan embodiment.

FIG. 18A depicts a schematic top view of a patterning device with afluid removal unit according to an embodiment.

FIG. 18B depicts a schematic side view of a patterning device with afluid removal unit according to FIG. 18A.

FIG. 19A depicts a schematic top view of a patterning device with afluid removal unit according to an embodiment.

FIG. 19B depicts a schematic side view of a patterning device with afluid removal unit according to FIG. 19A.

FIG. 20A depicts a schematic top view of a patterning device with afluid removal unit according to an embodiment.

FIG. 20B depicts a schematic side view of a patterning device with afluid removal unit according to FIG. 20A.

FIG. 21 depicts a schematic top view of a part of a lithographicapparatus according to an embodiment.

FIG. 22 depicts an example of decomposing a pattern to a high resolutionpattern and a low resolution pattern according to an embodiment.

FIG. 23 is a graph of data rate versus pattern complexity.

FIG. 24A, FIG. 24B, FIG. 24C and FIG. 24D depict various examples ofproducing a pattern using high resolution individually addressableelements and low resolution individually addressable elements withdifferent spot size ratios.

FIG. 25 is a flow diagram illustrating an example patterning processaccording to an embodiment.

One or more embodiments will now be described with reference to theaccompanying drawings. In the drawings, like reference numbers mayindicate identical or functionally similar elements.

DETAILED DESCRIPTION

One or more embodiments of a maskless lithographic apparatus, a masklesslithographic method, a programmable patterning device and otherapparatus, articles of manufacture and methods are described herein. Inan embodiment, a low cost and/or flexible maskless lithographicapparatus is provided. As it is maskless, no conventional mask is neededto expose, for example, ICs or flat panel displays.

In an embodiment, the lithographic apparatus is highly flexible. In anembodiment, the lithographic apparatus is scalable to substrates ofdifferent sizes, types and characteristics. Thus, the lithographicapparatus can enable multiple applications (e.g., IC, flat paneldisplay, packaging, etc.) with a single lithographic apparatus or usingmultiple lithographic apparatus using a largely common lithographicapparatus platform.

In an embodiment, the lithographic apparatus is low cost. In anembodiment, only common off-the-shelf components are used (e.g.,radiation emitting diodes, a simple movable substrate holder, and a lensarray). In an embodiment, pixel-grid imaging is used to enable simpleprojection optics. In an embodiment, a substrate holder having a singlescan direction is used to reduce cost and/or reduce complexity.

FIG. 1 schematically depicts a part of a lithographic projectionapparatus 100 according to an embodiment. Apparatus 100 includes apatterning device 104, an object holder 106 (e.g., an object table, forinstance a substrate table), and a projection system 108.

In an embodiment, the patterning device 104 comprises a plurality ofindividually addressable elements 102 to modulate radiation to apply apattern to beam 110. In an embodiment, the position of the plurality ofindividually addressable elements 102 can be fixed relative toprojection system 108. However, in an alternative arrangement, aplurality of individually addressable elements 102 may be connected to apositioning device (not shown) to accurately position one or more ofthem in accordance with certain parameters (e.g., with respect toprojection system 108).

In an embodiment, the patterning device 104 is a self-emissive contrastdevice. Such a patterning device 104 obviates the need for a radiationsystem, which can reduce, for example, cost and size of the lithographicapparatus. For example, the individually addressable elements 102 areradiation emitting diodes, such as light-emitting diodes (LEDs), organicLEDs (OLEDs), polymer LEDs (PLEDs), laser diodes (e.g., solid statelaser diodes), vertical external cavity surface emitting lasers(VECSELs), vertical cavity surface emitting lasers (VCSELs), or anycombination thereof. In an embodiment, the individually addressableelements 102 are all LEDs. In an embodiment, the individuallyaddressable elements 102 emit radiation having a wavelength in the rangeof about 380-440 nm, e.g., about 400 or 405 nm. In an embodiment, eachof the individually addressable elements 102 can provide an output powerselected from the range of 1-100 microwatts (μW). In an embodiment, eachof the individually addressable elements 102 can provide an outputcurrent of about 3 microamperes (μA). In an embodiment, each of theindividually addressable elements 102 has an emission cross-sectionalwidth of about 2 micrometers (μm) or less, e.g., about 1 micrometer orless (for example, assuming 1:1 optics; if using de-magnifying optics,e.g. 2:1 or 4:1, larger emission cross-sectional widths can be used,such as about 8 μm or less).

In an embodiment, the self-emissive contrast device comprises moreindividually addressable elements 102 than needed to allow a “redundant”individually addressable element 102 to be used if another individuallyaddressable element 102 fails to operate or doesn't operate properly.Further, more individually addressable elements 102 than might be neededcould be used to have elements 102 work together to deliver a certainpower or dose in case individual elements 102 can't provide sufficientoptical output alone or to have elements 102 “share the load” byreducing the usage of elements 102 from their maximum or designspecification.

The lithographic apparatus 100 comprises an object holder 106. In thisembodiment, the object holder comprises an object table 106 to hold asubstrate 114 (e.g., a resist-coated silicon wafer or glass substrate).The object table 106 may be movable in up to 6 degrees of freedom (e.g.,in at X and/or Y directions) and be connected to a positioning device116 to accurately position substrate 114 in accordance with certainparameters. For example, a positioning device 116 may accuratelyposition substrate 114 with respect to projection system 108 and/or thepatterning device 104. In an embodiment, movement of object table 106may be realized with the positioning device 116 comprising a long-strokemodule (coarse positioning) and optionally a short-stroke module (finepositioning), which are not explicitly depicted in FIG. 1. A similarsystem may be used to position the individually addressable elements102, such that, for example, the individually addressable elements 102can be moved in up to 6 degrees of freedom (e.g., in at X and/or Ydirections), e.g., scan in a direction substantially parallel with ascanning direction of the object table 106 and optionally step in anorthogonal direction to the scanning direction. Beam 110 mayalternatively/additionally be moveable, while the object table 106and/or the individually addressable elements 102 may have a fixedposition to provide the required relative movement. Such an arrangementmay assist in limiting the size of the apparatus.

In an embodiment, which may e.g. be applicable in the manufacture offlat panel displays, the object table 106 may be stationary andpositioning device 116 is configured to move substrate 114 relative to(e.g., over) object table 106. For example, the object table 106 may beprovided with a system to scan the substrate 114 across it at asubstantially constant velocity. Where this is done, object table 106may be provided with a multitude of openings on a flat uppermostsurface, gas being fed through the openings to provide a gas cushionwhich is capable of supporting substrate 114. This is conventionallyreferred to as a gas bearing arrangement. Substrate 114 is moved overobject table 106 using one or more actuators (not shown), which arecapable of accurately positioning substrate 114 with respect to the pathof beam 110. Alternatively, substrate 114 may be moved with respect tothe object table 106 by selectively starting and stopping the passage ofgas through the openings. In an embodiment, the object holder 106 can bea roll system onto which a substrate is rolled and positioning device116 may be a motor to turn the roll system to provide the substrate ontoan object table 106.

Projection system 108 (e.g., a quartz, glass, plastic (e.g., COC) and/orCaF₂ lens system or optical element, or a catadioptric system comprisinglens elements made from such materials, or a mirror system, or anoptical element (e.g., glass element) with an additional layer ofpolymer, or an optical element comprising a flat surface and a sphericalsurface, which can be modified to an aspherical surface using, e.g., apolymer layer, etc.) can be used to project the patterned beam modulatedby the individually addressable elements 102 onto a target portion 120(e.g., one or more dies) of substrate 114. Projection system 108 mayimage the pattern provided by the plurality of individually addressableelements 102 such that the pattern is coherently formed on the substrate114. Alternatively, projection system 108 may project images ofsecondary sources for which the elements of the plurality ofindividually addressable elements 102 act as shutters.

In this respect, the projection system may comprise a focusing element,or a plurality of focusing elements (herein referred to generically as alens array) e.g., a micro-lens array (known as an MLA) or a Fresnel lensarray, e.g. to form the secondary sources and to image spots onto thesubstrate 114. In an embodiment, the lens array (e.g., MLA) comprises atleast 10 focusing elements, e.g. at least 100 focusing elements, atleast 1,000 focusing elements, at least 10,000 focusing elements, atleast 100,000 focusing elements, or at least 1,000,000 focusingelements. In an embodiment, the number of individually addressableelements in the patterning device is equal to or greater than the numberof focusing elements in the lens array. In an embodiment, the lens arraycomprises a plurality of focusing elements, at least one focusingelement is optically associated with one or more of the individuallyaddressable elements in the array of individually addressable elements,e.g. with only one of the individually addressable elements in the arrayof individually addressable elements, or with 2 or more of theindividually addressable elements in the array of individuallyaddressable elements, e.g., 3 or more, 5 or more, 10 or more, 20 ormore, 25 or more, 35 or more, or 50 or more; in an embodiment, at leastone focusing element of the plurality of optical elements is opticallyassociated with less than 5,000 individually addressable elements, e.g.less than 2,500, less than 1,000, less than 500, or less than 100.

In an embodiment, the lens array comprises two or more focusing elements(e.g. more than 1,000, the majority, or about all) that are eachoptically associated with a plurality of individually addressableelements in a two-dimensional array.

In an embodiment, the patterning device 104 is movable at least in thedirection to and away from the substrate, e.g. with the use of one ormore actuators. Being able to move the patterning device to and awayfrom the substrate allows, e.g., for focus adjustment without moving thesubstrate or the lens array (e.g. for local focus adjustments onnon-flat substrates).

In an embodiment, the lens array comprises plastic focusing elements(which may be easy to make, e.g. injection molding, and/or affordable),where, for example, the wavelength of the radiation is greater than orequal to about 400 nm (e.g. 405 nm). In an embodiment, the wavelength ofthe radiation is selected from the range of about 350 nm-500 nm, e.g.,the range of about 375-425 nm. In an embodiment, the lens arraycomprises quartz or glass focusing elements.

In an embodiment, each or a plurality of the focusing elements may be anasymmetrical lens (e.g., having one or more asymmetric surfaces). Theasymmetry may be the same for each of the plurality of focusing elementsor may be different for one or more focusing elements of a plurality offocusing elements than for one or more different focusing elements of aplurality of focusing elements. An asymmetrical lens may facilitateconverting an oval radiation output into a circular projected spot, orvice versa.

In an embodiment, the focusing element has a high numerical aperture(NA) that is arranged to project radiation onto the substrate out of thefocal point to obtain a low NA for the system. A higher NA lens may bemore economic, prevalent and/or better quality than an available low NAlens. In an embodiment, low NA is less than or equal to 0.3, in anembodiment 0.18, 0.15 or less. Accordingly, a higher NA lens has a NAgreater than the design NA for the system, for example, greater than0.3, greater than 0.18, or greater than 0.15.

While, in an embodiment, the projection system 108 is separate from thepatterning device 104, it need not be. The projection system 108 may beintegral with the patterning device 108. For example, a lens array blockor plate may be attached to (integral with) a patterning device 104. Inan embodiment, the lens array may be in the form of individual spatiallyseparated lenslets, each lenslet attached to (integral with) one or moreindividually addressable elements of the patterning device 104 asdiscussed in more detail below.

Optionally, the lithographic apparatus may comprise a radiation systemto supply radiation (e.g., ultraviolet (UV) radiation) to the pluralityof individually addressable elements 102. If the patterning device is aradiation source itself, e.g. a laser diode array or a LED array, thelithographic apparatus may be designed without a radiation system, i.e.without a radiation source other than the patterning device itself, orat least a simplified radiation system.

The radiation system includes an illumination system (illuminator)configured to receive radiation from a radiation source. Theillumination system includes one or more of the following elements: aradiation delivery system (e.g., suitable directing mirrors), aradiation conditioning device (e.g., a beam expander), an adjustingdevice to set the angular intensity distribution of the radiation(generally, at least the outer and/or inner radial extent (commonlyreferred to as σ-outer and σ-inner, respectively) of the intensitydistribution in a pupil plane of the illuminator can be adjusted), anintegrator, and/or a condenser. The illumination system may be used tocondition the radiation that will be provided to the individuallyaddressable elements 102 to have a desired uniformity and intensitydistribution in its cross-section. The illumination system may bearranged to divide radiation into a plurality of sub-beams that may, forexample, each be associated with one or more of the plurality of theindividually addressable elements. A two-dimensional diffraction gratingmay, for example, be used to divide the radiation into sub-beams. In thepresent description, the terms “beam of radiation” and “radiation beam”encompass, but are not limited to, the situation in which the beam iscomprised of a plurality of such sub-beams of radiation.

The radiation system may also include a radiation source (e.g., anexcimer laser) to produce the radiation for supply to or by theplurality of individually addressable elements 102. The radiation sourceand the lithographic apparatus 100 may be separate entities, for examplewhen the radiation source is an excimer laser. In such cases, theradiation source is not considered to form part of the lithographicapparatus 100 and the radiation is passed from the source to theilluminator. In other cases the radiation source may be an integral partof the lithographic apparatus 100, for example when the source is amercury lamp.

In an embodiment, the radiation source, which in an embodiment may bethe plurality of individually addressable elements 102, can provideradiation having a wavelength of at least 5 nm, e.g. at least 10 nm, atleast 50 nm, at least 100 nm, at least 150 nm, at least 175 nm, at least200 nm, at least 250 nm, at least 275 nm, at least 300 nm, at least 325nm, at least 350 nm, or at least 360 nm. In an embodiment, the radiationhas a wavelength of at most 450 nm, e.g. at most 425 nm, at most 375 nm,at most 360 nm, at most 325 nm, at most 275 nm, at most 250 nm, at most225 nm, at most 200 nm, or at most 175 nm. In an embodiment, theradiation has a wavelength including 436 nm, 405 nm, 365 nm, 355 nm, 248nm, 193 nm, 157 nm, 126 nm, and/or 13.5 nm. In an embodiment, theradiation includes a wavelength of around 365 nm or around 355 nm. In anembodiment, the radiation includes a broad band of wavelengths, forexample encompassing 365 nm, 405 nm and 436 nm. A 355 nm laser sourcecould be used. In an embodiment, the radiation has a wavelength of about405 nm.

In operation of the lithographic apparatus 100, where the patterningdevice 104 is not radiation emissive, radiation is incident on thepatterning device 104 (e.g., a plurality of individually addressableelements) from a radiation system (illumination system and/or radiationsource) and is modulated by the patterning device 104.

Alternatively, in operation of the lithographic apparatus 100, where thepatterning device is self-emissive and comprises a plurality ofindividually addressable elements 102 (e.g., LEDs), the plurality of theindividually addressable elements are modulated by a control circuit(not shown) so that each of the individually addressable elements may beturned “ON” or “OFF” according to a desired pattern, where “ON” is aradiation emission state with higher intensity or dose than when “OFF”.In an embodiment, “ON” or “OFF” can include varying gray levels.

The patterned beam 110, after having been created by the plurality ofindividually addressable elements 102, passes through projection system108, which focuses beam 110 onto a target portion 120 of the substrate114.

With the aid of positioning device 116 (and optionally a position sensor134 on a base 136 (e.g., an interferometric measuring device thatreceives an interferometric beam 138, a linear encoder or a capacitivesensor)), substrate 114 can be moved accurately, e.g., so as to positiondifferent target portions 120 in the path of beam 110. Where used, thepositioning device for the plurality of individually addressableelements 102 can be used to accurately correct the position of theplurality of individually addressable elements 102 with respect to thepath of beam 110, e.g., during a scan.

Although the lithography apparatus 100 according to an embodiment isdescribed herein as being configured to expose a resist on a substrate,the apparatus 100 may be used to project a patterned beam 110 for use inresistless lithography.

The lithographic apparatus 100 may be of a reflective type (e.g.employing reflective individually addressable elements). Alternatively,the apparatus may be of a transmissive type (e.g. employing transmissiveindividually addressable elements).

The depicted apparatus 100 can be used in one or more modes, such as:

1. In step mode, the individually addressable elements 102 and thesubstrate 114 are kept essentially stationary, while an entire patternedradiation beam 110 is projected onto a target portion 120 at one go(i.e. a single static exposure). The substrate 114 is then shifted inthe X- and/or Y-direction so that a different target portion 120 can beexposed to the patterned radiation beam 110. In step mode, the maximumsize of the exposure field limits the size of the target portion 120imaged in a single static exposure.

2. In scan mode, the individually addressable elements 102 and thesubstrate 114 are scanned synchronously while a pattern radiation beam110 is projected onto a target portion 120 (i.e. a single dynamicexposure). The velocity and direction of the substrate relative to theindividually addressable elements may be determined by the (de-)magnification and image reversal characteristics of the projectionsystem PS. In scan mode, the maximum size of the exposure field limitsthe width (in the non-scanning direction) of the target portion in asingle dynamic exposure, whereas the length of the scanning motiondetermines the length (in the scanning direction) of the target portion.

3. In pulse mode, the individually addressable elements 102 are keptessentially stationary and the entire pattern is projected onto a targetportion 120 of the substrate 114 using pulsing (e.g., provided by apulsed radiation source or by pulsing the individually addressableelements). The substrate 114 is moved with an essentially constant speedsuch that the patterned beam 110 is caused to scan a line across thesubstrate 114. The pattern provided by the individually addressableelements is updated as required between pulses and the pulses are timedsuch that successive target portions 120 are exposed at the requiredlocations on the substrate 114. Consequently, patterned beam 110 canscan across the substrate 114 to expose the complete pattern for a stripof the substrate 114. The process is repeated until the completesubstrate 114 has been exposed line by line.

4. In continuous scan mode, essentially the same as pulse mode exceptthat the substrate 114 is scanned relative to the modulated beam ofradiation B at a substantially constant speed and the pattern on thearray of individually addressable elements is updated as the patternedbeam 110 scans across the substrate 114 and exposes it. A substantiallyconstant radiation source or a pulsed radiation source, synchronized tothe updating of the pattern on the array of individually addressableelements may be used.

Combinations and/or variations on the above described modes of use orentirely different modes of use may also be employed.

FIG. 2 depicts a schematic top view of a part of a lithographicapparatus according to an embodiment for use with substrates (e.g., 300mm wafers). As shown in FIG. 2, the lithographic apparatus 100 comprisesa substrate table 106 to hold a substrate 114. Associated with thesubstrate table 106 is a positioning device 116 to move the substratetable 106 in at least the X-direction as shown in arrow 123. Optionally,the positioning device 116 may move the substrate table 106 in theY-direction and/or Z-direction. The positioning device 116 may alsorotate the substrate table 106 about the X-, Y- and/or Z-directions.Accordingly, the positioning device 116 may provide motion in up to 6degrees of freedom. In an embodiment, the substrate table 106 providesmotion only in the X-direction, an advantage of which is lower costs andless complexity.

The lithographic apparatus 100 further comprises a plurality ofindividually addressable elements 102 arranged on a frame 160. Frame 160may be mechanically isolated from the substrate table 106 and itspositioning device 116. Mechanical isolation may be provided, forexample, by connecting the frame 160 to ground or a firm base separatelyfrom the frame for the substrate table 106 and/or its positioning device116. In addition or alternatively, dampers may be provided between frame160 and the structure to which it is connected, whether that structureis ground, a firm base or a frame supporting the substrate table 106and/or its positioning device 116.

In this embodiment, each of the individually addressable elements 102 isa radiation emitting diode, e.g., an LED. For the sake of simplicity,three rows of individually addressable elements 102 extending along theY-direction (and spaced in the X-direction) are shown in FIG. 2, eachrow having, in this embodiment, sufficient columns to extend across thewidth of the substrate; a greater number of rows of individuallyaddressable elements 102 may be arranged on the frame 160. In anembodiment, each of the individually addressable elements 102 isconfigured to provide a plurality of radiation beams. In an embodiment,each of the individually addressable elements 102 depicted in FIG. 2comprises a plurality of individually addressable elements 102 (thuseach circle labeled 102 in FIG. 2 represents a plurality of individuallyaddressable elements 102). In an embodiment, one or more rows ofindividually addressable elements 102 are staggered in the Y-directionfrom an adjacent row of individually addressable elements 102 as shownin FIG. 2. In an embodiment, the individually addressable elements 102are substantially stationary, i.e., they do not move significantly or atall during projection.

The lithographic apparatus 100, particularly the individuallyaddressable elements 102, may be arranged to provide pixel-grid imagingas described in more detail herein. However, in an embodiment, thelithographic apparatus 100 need not provide pixel-grid imaging. Rather,the lithographic apparatus 100 may project the radiation of theindividually addressable elements 102 onto the substrate in a mannerthat does not form individual pixels for projection onto the substratebut rather a substantially continuous image for projection onto thesubstrate.

Element 150 of lithographic apparatus 100 as depicted in FIG. 2 maycomprise an alignment sensor, a level sensor, or both. For example, inan embodiment, the lithographic apparatus 100 comprises an alignmentsensor 150. The alignment sensor is used to determine alignment betweenthe substrate 114 and, for example, the individually addressableelements 102 before and/or during exposure of the substrate 114. Theresults of the alignment sensor 150 can be used by a controller of thelithographic apparatus 100 to control, for example, the positioningdevice 116 to position the substrate table 106 to improve alignment. Inaddition or alternatively, the controller may control, for example,responsive to a signal from sensor 150, a positioning device associatedwith the individually addressable elements 102 to position one or moreof the individually addressable elements 102 (including, for example,positioning one or more of the elements 102 relative to one or moreother elements 102) to improve alignment and/or, responsive to a signalfrom sensor 150, a deflector associated with the individuallyaddressable elements 102 to position one or more of the beams(including, for example, positioning one or more of the beams relativeto one or more other beams) to improve alignment. In an embodiment, thealignment sensor 150 may include pattern recognitionfunctionality/software to perform alignment.

In an embodiment, the lithographic apparatus 100, in addition oralternatively, comprises a level sensor 150. The level sensor 150 isused to determine whether the substrate 106 is level with respect to theprojection of the pattern from the individually addressable elements102. The level sensor 150 can determine level before and/or duringexposure of the substrate 114. The results of the level sensor 150 canbe used by a controller of the lithographic apparatus 100 to control,for example, the positioning device 116 to position the substrate table106 to improve leveling. In addition or alternatively, the controllermay control, for example, responsive to a signal from sensor 150, apositioning device associated with a projection system 108 (e.g., a lensarray) to position an element of the projection system 108 (e.g., alens, or a smaller lens array, of a lens array, including, for example,positioning a lens, or a smaller lens array, of a lens array relative toanother lens, or another smaller lens array, of the lens array) toimprove leveling. In an embodiment, the level sensor may operate byprojecting an ultrasonic beam at the substrate 106 and/or operate byprojecting an electromagnetic beam of radiation at the substrate 106.

In an embodiment, results from the alignment sensor and/or the levelsensor may be used to alter the pattern provided by the individuallyaddressable elements 102. The pattern may be altered to correct, forexample, distortion, which may arise from, e.g., optics (if any) betweenthe individually addressable elements 102 and the substrate 114,irregularities in the positioning of the substrate 114, unevenness ofthe substrate 114, etc. Thus, results from the alignment sensor and/orthe level sensor can be used to alter the projected pattern to effect anon-linear distortion correction. Non-linear distortion correction maybe useful, for example, for flexible displays, which may not haveconsistent linear or non-linear distortion.

In operation of the lithographic apparatus 100, a substrate 114 isloaded onto the substrate table 106 using, for example, a robot handler(not shown). The substrate 114 is then displaced in the X-direction asshown in the arrow 123 under the frame 160 and the individuallyaddressable elements 102. The substrate 114 is measured by the levelsensor and/or the alignment sensor 150 and then is exposed to a patternusing individually addressable elements 102. For example, the substrate114 is scanned through the focal plane (image plane) of the projectionsystem 108, while the substrate is moving and the individuallyaddressable elements 102 are switched at least partially or fully “ON”or “OFF” in the patterning device 104. Features corresponding to thepattern of the patterning device 104 are formed on the substrate 114.The individually addressable elements 102 may be operated, for example,to provide pixel-grid imaging as discussed herein.

In an embodiment, the substrate 114 may be scanned completely in thepositive X-direction and then scanned completely in the negativeX-direction. In such an embodiment, an additional level sensor and/oralignment sensor 150 on the opposite side of the individuallyaddressable elements 102 may be required for the negative X-directionscan.

FIG. 3 depicts a schematic top view of a part of a lithographicapparatus according to an embodiment for exposing substrates in themanufacture of, for instance, flat panel displays (e.g., LCDs, OLEDdisplays, etc.). Like the lithographic apparatus 100 shown in FIG. 2,the lithographic apparatus 100 comprises a substrate table 106 to hold aflat panel display substrate 114, a positioning device 116 to move thesubstrate table 106 in up to 6 degrees of freedom, an alignment sensor150 to determine alignment between the individually addressable elements102 and the substrate 114, and a level sensor 150 to determine whetherthe substrate 114 is level with respect to the projection of the patternfrom the individually addressable elements 102.

The lithographic apparatus 100 further comprises a plurality ofindividually addressable elements 102 arranged on a frame 160. In thisembodiment, each of the individually addressable elements 102 is aradiation emitting diode, e.g., an LED. For the sake of simplicity,three rows of individually addressable elements 102 extending along theY-direction are shown in FIG. 3 and having sufficient columns to coverthe width of the substrate; a greater number of rows of individuallyaddressable elements 102 may be arranged on the frame 160. In anembodiment, each of the individually addressable elements 102 isconfigured to provide a plurality of radiation beams. In an embodiment,each of the individually addressable elements 102 depicted in FIG. 3comprises a plurality of individually addressable elements 102 (thuseach circle labeled 102 in FIG. 3 represents a plurality of individuallyaddressable elements 102). Further, in an embodiment, a number of therows of individually addressable elements 102 are staggered in theY-direction from one or more adjacent rows of individually addressableelements 102 as shown in FIG. 3. The lithographic apparatus 100,particularly the individually addressable elements 102, may be arrangedto provide pixel-grid imaging. In an embodiment, the individuallyaddressable elements 102 are substantially stationary, i.e., they do notmove significantly during projection.

In operation of the lithographic apparatus 100, a panel displaysubstrate 114 is loaded onto the substrate table 106 using, for example,a robot handler (not shown). The substrate 114 is then displaced in theX-direction as shown in arrow 123 under the frame 160 and theindividually addressable elements 102. The substrate 114 is measured bythe level sensor and/or the alignment sensor 150 and then is exposed toa pattern using individually addressable elements 102. One or morelenses may be used to project the patterning beams from the individuallyaddressable elements 102 to the substrate. The individually addressableelements 102 may be operated, for example, to provide pixel-grid imagingas discussed herein.

As discussed above, a plurality of individually addressable elements 102are optically associated with a lens of projection system 108. In anembodiment, the patterning beams from the plurality of individuallyaddressable elements 102 substantially cover the field of view of theassociated lens of projection system 108. In an embodiment, a pluralityof individually addressable elements 102 collectively forms atwo-dimensional emitter array, each array associated with a single lensof projection system 108. And so, in an embodiment, there are provided aplurality of emitter arrays, each array associated with a single lens ofa lens array (extending in the X-Y plane) of projection system 108.Thus, in an embodiment, a single lens forms all of, or part of, theprojection system 108 for an array of individually addressable elements102.

FIG. 4A depicts a schematic side view of a part of a lithographicapparatus according to an embodiment. As shown in FIG. 4A, thelithographic apparatus 100 comprises a patterning device 104 and aprojection system 108. The patterning device 104 comprises an emitterarray 101. As discussed above, the emitter array 101 comprises aplurality of individually addressable elements 102 in a two-dimensionalarray. In an embodiment, each of the individually addressable elements102 is a LED.

The projection system 108 comprises two lenses 122, 124 along an opticalaxis. The first lens 122, a field lens, is arranged to receive themodulated radiation beams 110 from the emitter array 101. The radiationbeams 110 diverge toward the field lens 122. The field lens 112 theneffectively collimates the radiation beams and directs them toward asecond lens 124, an imaging lens. The lens 124 focuses the beams 110onto the substrate 114. In an embodiment, the lens 124 can provide a NAof 0.15 or 0.18. In an embodiment, the lens 122 and/or the lens 124 maybe moved in up to 6 degrees of freedom (e.g., in the X-Y-Z directions)using an actuator.

As shown in FIG. 4A, a free working distance 128 is provided between thesubstrate 114 and the lens 124. This distance allows the substrate 114and/or the lens 124 to be moved to allow, for example, focus correction.In an embodiment, the free working distance is in the range of 1-3 mm,e.g., about 1.4 mm.

In an embodiment, the projection system 108 can be a 1:1 projectionsystem in that the array spacing of the image spots on the substrate 114is the same as the array spacing of the individually addressableelements 102 of the patterning device 104. To provide improvedresolution, the image spots can be much smaller than the size of eachindividually addressable element 102 of the patterning device 104 byadjusting the field lens 122, the imaging lens 124, or both.

Referring to FIG. 4B, in an embodiment, the patterning device 104comprises two or more emitter arrays 101. Accordingly, two or moreprojection systems 108 are used to project the patterning beams fromsuch a patterning device 104 to the substrate 114. In an embodiment,there may be 100's, or 1000's of emitter arrays, each emitter arrayassociated with a projection system 108, comprising lens 122 and/or lens124. In an embodiment, the cross-sectional width (e.g., diameter) 109 oflens 122 and/or 124 is 1 millimeter (mm). FIG. 4B depicts an embodimentof a plurality of emitter arrays 101 employed in the patterning device104 is depicted. Different sets of the modulated radiation beams 110,each set corresponding to an emitter array 101 of two or more emitterarrays 101 in the patterning device 104, pass through respective lenses122 and 124 and are focused to the substrate 114. As a result, an arrayof radiation spots (each spot having a size of, for example, around 1μm) is exposed onto the substrate 114. The individually addressableelements 102 of the patterning device 104 may be arranged at a pitch,which may result in the same pitch of imaging spots at substrate 114.

In an embodiment, each emitter array 101 and the associated lens 122and/or lens 124 may be collectively considered as an individual opticalengine component. The individual optical engine component may bemanufactured as a unit for easy replication. In an embodiment, theindividual optical engine component may be used to print brushessubstantially covering the field of view of the lens 122, 124. Moreover,frame 160 may be configured to be expandable and configurable to easilyadopt any number of such optical engine components. In this way, animproperly working optical engine component (e.g., if an individuallyaddressable element of emitter array 101 is not working properly) may beeasily replaced with a functioning optical engine component.

Referring to FIG. 5, a highly schematic top view of an individualoptical engine component 500 is depicted. The individual optical enginecomponent 500 comprises an emitter array 101 and lens 122 and/or 124. Inan embodiment, the emitter array 101 comprises a plurality ofindividually addressable elements 102 arranged in a two-dimensionalarray, substantially covering a field of view area of the lens 122, 124.As shown in FIG. 5, the emitter array 101 comprises 225 individuallyaddressable elements 102 arranged in a square 15×15 array in which eachside of the array is, for example, about 70 μm long. Thus, the diagonalof the array is about 100 μm long, approximately equal to the width(e.g., diameter) of the field of view of the lens 122, 124. In anembodiment, the cross-sectional width (e.g., diameter) 502 of lens 122and/or 124 is about 1 millimeter (mm). In an embodiment, the spot sizeof the beam of an individually addressable element 102 is about 1micron. In an embodiment, each individually addressable element 102delivers about 3 μW optical power or less onto the substrate (which is,for example, for a flat panel display application for a scanning speedof around 10 mm/s and resist sensitivity of around 20 mJ/cm²). In anembodiment, the pitch, defined as the distance between centers ofadjacent individually addressable elements 102, is, e.g., about 5 μm. Inan embodiment, the array is imaged (1:1) onto the substrate 114 withdoublets 122, 124. In an embodiment, the lenses 122, 124 are arranged atabout 1 mm pitch.

Each individually addressable element 102 emits an electromagneticradiation toward the substrate 114, thereby generating a radiation spoton the substrate 114. As shown in FIG. 5, the emitter array 101 issituated at an angle θ relative to the scanning direction 123 ofrelative movement between the substrate 114 and the individuallyaddressable elements 102 (e.g., the direction 123 of movement of thesubstrate 114). This is so that, when there is relative movement betweenthe substrate 114 and the individually addressable elements 102 in thescanning direction, each radiation spot effectively passes over adifferent area of the substrate (although there can be some overlap),thereby enabling production of a brush 503 of modulated radiation whosewidth is related to the field of view of the lens 122. In an embodiment,the width 501 of the brush 503 is 70 μm. In an embodiment, the angle θis at most 20°, 10°, for instance at most 5°, at most 3°, at most 1°, atmost 0.5°, at most 0.25°, at most 0.10°, at most 0.05°, or at most0.01°. In an embodiment, the angle θ is at least 0.0001°, e.g. at least0.001°. The angle of inclination θ is determined in accordance with theimage spot size (which is a function of working distance between thesubstrate and the lens 122, 124), the pitch between adjacent radiationspots, and the field of view of the lens 122, 124.

FIG. 6 illustrates schematically a top view of how the pattern on thesubstrate 114 may be generated. The filled in circles represent thearray of spots S projected onto the substrate 114 by individuallyaddressable elements 102 in the emitter array 101. The substrate 114 ismoved relative to the projection system 108 in the X-direction as aseries of exposures are exposed on the substrate 114. The open circlesrepresent spot exposures SE that have previously been exposed on thesubstrate 114. As shown, each spot projected onto the substrate 114 byindividually addressable elements 102 in the emitter array 101 exposes acolumn R of spot exposures on the substrate 114. The complete patternfor the substrate 114 is generated by the sum of all the columns R ofspot exposures SE exposed by each of the spots S. Such an arrangement iscommonly referred to as “pixel grid imaging.” It will be appreciatedthat FIG. 6 is a schematic drawing and that spots S and/or the spotexposures SE exposed by different spots S may overlap in practice.

Similar to that shown in FIG. 5, the array of radiation spots S isarranged at an angle θ relative to the scanning direction (in thisexample, the edges of the substrate 114 lie parallel to the X- andY-directions). This is done so that, when there is relative movementbetween the substrate 114 and the individually addressable elements 102in the scanning direction, each radiation spot will effectively passover a different area of the substrate 114, thereby allowing forproducing a brush in a single scan. As discussed above, the angle ofinclination θ is determined in accordance with the image spot size, thepitch between adjacent radiation spots, and the field of view of thelens 122, 124.

Various embodiments may be employed to write patterns to cover the wholesurface area of the substrate 114 by using one or more individualoptical engine components 500. Firstly, in respect of the brush 503, inan embodiment, an optical engine component 500 is large enough to fullyexpose the width of the brush 503. If an optical engine component 500 isnot large enough to fully expose the width of the brush 503 in a singlescan, various embodiments can be used to fully cover the brush 503width. In an embodiment, an optical engine component 500 is scannedmultiple times while in between these scans a small motion is made in adirection orthogonal to the scan direction to “fill” in the gaps. In anembodiment, a plurality of optical engine components 500 are providedalong the scan direction but that are situated at an offset in adirection orthogonal to the scan direction, thus the second, third, etc.optical engine component 500 fills the gaps left by a first opticalengine component 500.

Then, it is desirable to expose the full substrate (e.g., wafer, flatpanel display, etc.) using a plurality of brushes 503 (e.g., brushes 503having a width of, e.g., 70 microns). Accordingly, a plurality ofoptical engine components 500 is provided. In an embodiment, thesubstrate is mostly fully covered with optical engine components 500 ata pitch of, e.g., 1 mm. Then, relative movement is provided between theoptical engine components 500 and the substrate 114 to scan multipletimes in a meandering fashion. In this embodiment, the relative motionbetween optical engine components 500 and the substrate can be limitedto, e.g., about 1 mm in both orthogonal directions X and Y. So, if therelative movement between each of the optical engine components 500 andthe substrate is repeated over 1 mm² in a meandering fashion (i.e.,including an offset in the direction perpendicular to the scan directionfor each scan) with brush strokes of about 70 microns width, effectivelyall areas on the substrate can be exposed. Redundancy (e.g., usinganother individually addressable element to expose an area of anindividually addressable element 102 that fails or doesn't workproperly) can be implemented by enlarging the scan range. For example,if the scan range is 2 mm rather than 1 mm, a plurality of opticalengine components 500 can then contribute to the exposure of an area onthe substrate associated primarily with one of the optical enginecomponents 500.

In an embodiment, wherein the substrate is relatively large and it isnot necessary or possible to cover the entire area of the substrate withoptical engine components 500 (e.g., because the collective radiationpower is not needed), optical engine components 500 can be provided soas to cover the width of the substrate in a direction orthogonal to thescan direction, e.g., as shown in FIGS. 2 and 3. In this manner, thesubstrate could be exposed in a single scanning pass of relativemovement between the optical engine components 500 and the substrate. Inan embodiment, there are sufficient columns of optical engine components500 such that the full substrate width can be exposed in a single scan.So, e.g. if one optical engine component exposes a width of 70 micronsat a pitch of 1 mm, 15 rows of optical engine components 500 (arrangedalong the scan direction and displaced from each other along thedirection orthogonal to the scan direction such that the respectivebrushes of the optical engine components 500 overlap) should besufficient for full exposure. Of course, a sufficient number of columnsof optical engine components 500 would be provided along the Y-directionto cover the width of the substrate. More rows can be added in case moreradiation power is needed (e.g., a same location on the substrate can beexposed multiple times—a first time by a first optical engine componentand then again by another optical engine component—and/or to provideredundancy as discussed above).

In an embodiment, if less radiation power is required and the radiationcan be modulated at a high frequency, the substrate can be scanned inone direction over its entire length and then a meander can be providedover, e.g., 1 mm in the orthogonal direction to the scan direction.Thus, the optical engine components 500 may not collectively extendacross the width of the substrate in the Y-direction. In that case, theoptical engine components 500 may collectively write a first portion ofthe substrate in a first scan, then an offset in the Y-direction isapplied and then one or more further scans (e.g., in reverse direction,then forward direction, and so on, i.e., a meandering fashion) can beapplied to expose the remaining portion of the substrate. Like previousembodiments, redundancy can be implemented by meandering over more than,e.g., 1 mm. For example, with a 4 mm meander, there is a plurality ofoptical engine components 500 contributing to the exposure of a singlearea on the substrate designated primarily for a particular opticalengine component 500.

In an embodiment, a brush produced on the substrate 114 in a scan isslightly overlapped with a brush produced in a previous scan.

FIGS. 7A, 7B, 7C, 7D and 7E depict schematic diagrams of a manufacturingmethod, e.g., for manufacturing a flat panel display. In FIG. 7A, acolumn 700 of individually addressable elements 702 (such asindividually addressable elements 102) is situated at an angle αrelative to the scanning direction 705 of relative movement between thesubstrate 114 (not shown in FIG. 7 for convenience but would be above orbelow elements 702) and the individually addressable elements 702. Thepitch 703 between adjacent individually addressable elements 702 isabout 5 μm. Each individually addressable element 702 emitselectromagnetic radiation toward the substrate 114, thereby generating aradiation spot on the substrate 114. Therefore, when there is relativemovement between the substrate 114 and the individually addressableelements 702 in the scanning direction 705, the radiation spotsgenerated by different individually addressable elements 702 will passover different areas of the substrate 114 (although there can be overlapbetween the areas covered by two or more of the individually addressableelements), thus producing a plurality of radiation lines 704 (brushlines of a brush) each with a width of about 1 μm. The turning “ON” or“OFF” of the individually addressable elements 702 is timed so that theappropriate pattern is formed along the length of each radiation line704 on the substrate 114. In an embodiment, the emitter size of eachindividually addressable element is about 1 μm; so, in an embodiment,the radiation spot size is about 1 μm. In an embodiment, the effectivepitch 701 (i.e., the displacement in the direction perpendicular to thescanning direction 705) between the adjacent individually addressableelements 702 is about 0.4 μm.

Additionally, the gray scale factor, which is the inverse of theeffective pitch (or typically the effective pitch is determined based onthe gray scale factor and is the inverse of the gray scale factor), isequal to about 2.5. The gray scale factor may be used to indicate thedegree of overlap between adjacent radiation lines. For example, a largegray scale factor indicates a high degree of overlap, and a small grayscale factor indicates a low degree of overlap. The gray scale factor(and thus the effective pitch) is a design parameter based on, e.g.resist ability to form the pattern in response to the radiation from thespots, line width roughness specification, etc. It specifies the ratiobetween the optical spot size on the substrate and the required designgrid (effective spot spacing or overlap) (e.g. 0.4 μm where the spotsize is 1 μm and so the gray scale factor is 2.5) to expose patternswith sufficient quality. In an embodiment, a column 700 comprises 15individually addressable elements 702, each of which produces aradiation line 704 with a width of about 1 μm on the substrate 114. Asshown in FIG. 7A, the adjacent radiation lines 704 have a significantoverlap. As a result, the radiation lines 704 are stitched together andcollectively generate a continuous brush line. For example, consideringa lens placement error of 0.5 μm on both sides of the row 700, the row700 may collectively generate a brush line with a width of about 5 μm.

As shown in FIG. 7B, a plurality of the columns 700 are stackedgenerally in parallel to form an emitter array 710. Each column 700 issituated at the angle α relative to the scanning direction (i.e., theX-direction). In an embodiment, the pitch between adjacent columns isthe same as the pitch 703 between adjacent individually addressableelements in the column 700. The brush lines produced by adjacent columns700 of individually addressable elements 702 may have slight overlap sothat the brush lines produced by all the columns 700 in the emitterarray 710 collectively produce a brush with a brush width of about 70μm, which effectively covers the field of view of the lens 122, 124located between the emitter array 710 and the substrate. In anembodiment, the emitter array 710 comprises 15 rows 700 of theindividually addressable elements 702. Since each row 700 may produce abrush line with a width of about 5 μm, the emitter array may thereforeproduce a brush with a brush width of about 70 μm when the adjacentbrush lines have appropriate overlap.

In FIG. 7C, an emitter array 710 is associated with a lens 715 (such aslens 122, 124), forming an individual optical engine component 718. Inan embodiment, the cross-sectional width (e.g., diameter) of the lens715 is about 1 mm, and the field of view of the lens 715 is about 100μm. A plurality of the individual optical engine components furtherforms a column 720 of the individual optical engine components 718. Inan embodiment, the lenses 715 of adjacent individual optical enginecomponents 718 are in contact or near contact. In this case, the spacingbetween emitter arrays 710 in the adjacent individual optical enginecomponents 718 is determined by the cross-sectional width (e.g.,diameter) of the lenses 715. The column 720 of the individual opticalengine components is situated at an angle β relative to the scanningdirection (i.e., the X-direction). The angle β is determined based on,for example, the brush width (e.g., about 70 μm), the cross-sectionalwidth (e.g., diameter) of the lens 715 and the location of other opticalengine components 718. The angle is provided so that, when there isrelative movement between the substrate 114 and the optical enginecomponents 718 in the scanning direction (i.e., the X-direction), thebrushes generated on the substrate 114 by the individual optical enginecomponents of a column 720 may have a slight overlap with one or moreother brushes (e.g., adjacent brushes, a brush in another row(comprising a plurality of columns) of optical engine components, etc.).Further, in an embodiment, a set of brushes (and thus optical enginecomponents 718) may collectively cover (“brush”) an area on thesubstrate with a width substantially equal to the cross-sectional widthof the lens 715. For example, column 720 can comprise 15 individualoptical engine components. Each individual optical engine component maygenerate a brush with a brush width of 70 μm. By carefully selecting theangle β, a column 720 of individual optical engine components 718 cancollectively cover an area on the substrate with a width of about 1 mm.

In FIG. 7D, a micro-lens array (MLA) module 730 is depicted. The MLAmodule 730 comprises a plurality of columns 720 of individual opticalengine components 718 arranged in essentially in parallel. The columns720 of individual optical engine components 718 are situated at theangle β relative to the scanning direction (the X-direction) so that thebrush produced by the first individual optical engine component in acolumn (e.g., the individual optical engine component 715) has slightoverlap with the brush produced by the last individual optical enginecomponent in the adjacent column (e.g. the individual optical enginecomponent 727), while the optical engine components 718 in the rows of acolumn 720 overlap with each other. Therefore, the brushes generated bythe individual optical engine components in the MLA module 730 arestitched together. In an embodiment, columns 720 of individual opticalengine components 718 in a MLA module 730 are in contact with theadjacent columns 720 of individual optical engine components 718, e.g.,their lenses 715 are in contact or near contact. The number of columns720 in an MLA module 730 is proportional to the width of area on thesubstrate that the MLA module 730 is intended to cover. In anembodiment, a MLA module 730 comprises 30 columns 720 of individualoptical engine components. As described above, each column 720 ofindividual optical engine components can cover an area with a width ofabout 1 mm. Therefore, a MLA module 730 with 30 columns may collectivelyproduce a pattern that covers an area on the substrate 114 with a widthof about 30 mm. Ten MLA modules may be provided to cover a substratewith a width (e.g., diameter) of about 300 mm. It is appreciated thatthe MLA module 730 may comprise any number of columns 720 of theindividual optical engine components.

FIG. 7E depicts a patterning device 740 (e.g., the patterning device104), e.g., in manufacturing of a flat panel display. The patterningdevice 740 comprises a row 735 of MLA modules 730. For a single passscan, the number of MLA modules 730 provided in the row 735 is typicallydetermined by the width of the substrate 114 and the width of thepattern produced by each MLA module 730. For example, if the substrate114 is 3 m wide, and each MLA module 730 is capable of covering an areaon the substrate with a width of about 30 mm, at least 100 MLA modules730 should be provided in the row 735 of the MLA modules 730. The row735 is situated perpendicular to the scanning direction, and each MLAmodule 730 in the row 735 is situated at the angle β with relative tothe scanning direction (i.e., the X-direction). The pitch betweenadjacent MLA modules 730 is carefully chosen so that the patternsproduced by adjacent MLA modules 730 have a slight overlap. As a result,the row 735 of MLA modules 730 can collectively cover the whole width ofthe substrate 114 (e.g., 3 m).

In an embodiment, the patterning device 740 comprises two or moreidentical rows 735 of the MLA modules 730 stacked in essentiallyparallel and aligned in the scanning direction (i.e., the X-direction).This arrangement can, for example, allow at least part of a “redundant”MLA module 730 (e.g., one or more individually addressable elements 102in a MLA module 730) in another 735 to be used when a corresponding partof a MLA module 730 in another row 735 (e.g., the first row) fails tooperate or doesn't operate properly. In addition or alternatively, oneor more extra rows 735 of the MLA modules 730 may have an advantage incontrolling thermal load on the individually addressable elements 102 inthe MLA modules 730. For example, a first row of the MLA modules 730 maybe used for a certain period and then a second row is used for anotherperiod while the first row cools, and so on.

In an embodiment, the plurality of rows 735 of the MLA modules 730 maybe operated at a fraction of their operating capacity at steady state.For example, the MLA modules 730 in each row 735 may be operated ataround 80% of their capacity during steady state and should at leastpart of one or more MLA modules 730 in one or more rows fail or notoperate properly, the remaining MLAs may be operated at a higher percentat steady state (e.g., 88% of their capacity) to provide close to or thesame desired radiation power and brightness.

In photolithography, a desired feature may be created on a substrate byselectively exposing a layer of resist on a substrate to radiation, e.g.by exposing the layer of resist to patterned radiation. Areas of theresist receiving a certain minimum radiation dose (“dose threshold”)undergo a chemical reaction, whereas other areas remain unchanged. Thethus created chemical differences in the resist layer allow fordeveloping the resist, i.e. selectively removing either the areas havingreceived at least the minimum dose or removing the areas that did notreceive the minimum dose. As a result, part of the substrate is stillprotected by a resist whereas the areas of the substrate from whichresist is removed are exposed, allowing e.g. for additional processingsteps, for instance selective etching of the substrate, selective metaldeposition, etc. thereby creating the desired feature. In an embodiment,at least part of two or more MLA modules 730 in two or more rows in FIG.7E collectively provide enough radiation dose to allow such chemicalreaction to take place in a corresponding area of the substrate 114.Thus, an area on the substrate can be exposed to radiation a pluralityof times by different optical engine components 718, either in the sameMLA module 730 or desirably in different MLA modules 730.

In the above discussions, an emitter array 101 is described as beingcapable of producing a whole, contiguous brush, on the surface of thesubstrate 114, that effectively covers the field of view of the lens122, 124. However, in an embodiment, this need not or may not be thecase. The capability of producing a whole brush using an emitter array101 depends on one or more factors selected from: the pitch betweenadjacent individually addressable elements 102, the field of view of thelens 122, 124, and/or the angle at which the emitter array 101 issituated relative to the scanning direction. In many examples, the lens122, 124 is specified at the outset (e.g., only certain lens sizes areavailable and/or a desired NA is required) and so the field of view isdetermined. In this case, the capability of producing the whole brush byan emitter array 101 depends on, for example, the pitch between adjacentindividually addressable elements 102 in the emitter array 101 and theangle at which the emitter array 101 is situated relative to thescanning direction.

Referring to FIG. 8A, a schematic top view of an emitter array 800 isdepicted. Similar to as discussed above, the emitter array 800 is a partof an individual optical engine component and is optically associatedwith a lens (e.g., the lens 122, 124). In an embodiment, the field ofview of the lens is determined to be 100 μm. As shown, the emitter array800 comprises a plurality of columns (e.g., columns R1-R3) ofindividually addressable elements 807 (such as individually addressableelements 102 and includes elements 803, 804, 805, 806). Each column ofthe individually addressable elements comprises a plurality ofindividually addressable elements with a pitch 801 of, e.g., about 5 μmbetween adjacent individually addressable elements. In an embodiment,the spot size of each individually addressable element is about 1 μm. Inan embodiment, each of the individually addressable elements is a LED.The columns of individually addressable elements (e.g., the columnsR1-R3) are situated essentially in parallel also with a pitch 801between adjacent columns of the individually addressable elements.Therefore, in an embodiment, the emitter array 800 forms a square arrayof individually addressable elements 807, i.e., the four sides 802 ofthe emitter array 800 have essentially equal lengths. In an embodiment,each side 802 of the emitter array 800 is 70 μm long. Therefore, thediagonal of the emitter array 800 is about 100 μm long, which isapproximately equal to the field of view of the lens associated with theemitter array 800.

The emitter array 800 is situated at an angle α1 relative to thescanning direction 808. This is done so that, when the substrate (notshown) is irradiated by the beams from the emitter array 800 and thereis relative movement between the substrate 114 and the emitter array 800in the scanning direction 808, each radiation spot from the individuallyaddressable element will effectively pass over a different area of thesubstrate, thereby allowing for production of different radiation lines.

As shown, the radiation lines have a slight overlap with adjacentradiation lines written by the individually addressable elements fromthe same column (e.g., the column R2). Further, the radiation linewritten by the first individually addressable element 806 of the columnR2 has an overlap with the radiation line written by the lastindividually addressable element 803 of the column R1. In addition, theradiation line written by the last individually addressable element 804of the column R2 has overlap with the radiation line written by thefirst individually addressable element 805 of the column R3. Therefore,the radiation lines written by all the columns of the individuallyaddressable elements in the emitter array 800 may be stitchedcollectively to generate a brush with a width of, e.g., 70 μm.

Now, referring to FIG. 8B, a schematic top view of a further emitterarray 810 is depicted. The emitter array 810 is a part of an individualoptical engine component and is optically associated with a lens similarto that described in FIG. 8A. In an embodiment, the field of view of thelens is, for example, 100 μm. As shown, the emitter array 810 comprisesa plurality of columns of individually addressable elements (e.g.,columns R1′-R3′). Each column of individually addressable elementscomprises a plurality of individually addressable elements with a pitch809 of, e.g., about 7 μm between adjacent individually addressableelements. The size of each individually addressable element is about 1μm. In an embodiment, each of the individually addressable elements is aLED. The columns of individually addressable elements (e.g., the columnsR1′-R3′) are situated essentially in parallel with the pitch 809 betweenadjacent columns of the individually addressable elements. Therefore, inan embodiment, the emitter array 810 forms a square array ofindividually addressable elements 807, i.e., the four sides 802 of theemitter array 810 have essentially equal lengths. In this case, the sizeof the emitter array 810 is similar to the size of the emitter array800. In an embodiment, each side 802 of the emitter array 810 is 70 μmlong. Therefore, the diagonal of the emitter array 810 is about 100 μmlong, which is approximately equal to the field of view of the lensassociated with the emitter array 810.

The emitter array 810 is situated at an angle β1 relative to thescanning direction 818. This is done so that, when the substrate (notshown) is irradiated by the beams from the emitter array 810 and thereis relative movement between the substrate 114 and the emitter array 810in the scanning direction, each radiation spot from the individuallyaddressable elements will pass over a different area of the substrate,thereby allowing radiation lines written by the same column (e.g., thecolumn R2′) of individually addressable elements to have a slightoverlap with adjacent radiation lines. But, due to the larger pitch(i.e., about 7 μm) compared with that in FIG. 8A (i.e., about 5 μm), theangle β1 is smaller than the angle α1.

Further, although the radiation lines written by the same column (e.g.,the column R2′) of individually addressable elements may stitchtogether, these radiation lines may not stitch with those written by oneor more adjacent columns (e.g., the columns R1′ and R3′) of individuallyaddressable elements. For example, the radiation line written by thefirst individually addressable element 816 of column R2′ may notslightly overlap with the radiation line written by the lastindividually addressable element 813 of column R1′. Similarly, theradiation line written by the last individually addressable element 814of column R2′ may not slightly overlap with the radiation line writtenby the first individually addressable element 815 of column R3′. As aresult, the emitter array 810 may not be capable of producing a wholebrush with a width of 70 μm on the substrate 114. Furthermore,increasing the angle β1 in a counterclockwise direction may decrease thegap between the radiation lines produced by adjacent columns ofindividually addressable elements (e.g., R1′ and R2′, and/or R2′ andR3′). However, this may create a gap between adjacent radiation linesproduced by adjacent individually addressable elements in the samecolumn (e.g., R2′). In either case, the emitter array 810 may produceundesirable “zebra” lines due to the relatively large pitch betweenadjacent individually addressable elements. To resolve this issue, twoor more emitter arrays 810 with a displacement in a directionperpendicular to the scanning direction may be used to collectivelycreate a brush.

FIGS. 9A, 9B, 9C, 9D and 9E depict schematic diagrams of a manufacturingmethod, e.g., for manufacturing a flat panel display. In FIG. 9A, acolumn 907 of individually addressable elements 902 represented by solidcircles is situated at angle θ relative to the scanning direction 901.In an embodiment, the pitch 911 between adjacent individuallyaddressable elements 902 is about 7 μm. Each individually addressableelement 902 emits electromagnetic radiation toward the substrate 114,thereby generating a radiation spot on the substrate 114. Therefore,when there is relative movement between the substrate 114 and theindividually addressable elements 902 in the scanning direction 901, theradiation spots generated by different individually addressable elements902 will pass over different areas of the substrate 114, therebyallowing production of a plurality of radiation lines 903 each with awidth of 1 μm. The turning “ON” or “OFF” of the individually addressableelements 902 is timed so that the desired pattern is produced in eachradiation line 903 on the substrate 114. In an embodiment, the radiationspot size is 1 μm. Due to the relatively large pitch (i.e., about 7 μmversus about 5 μm), the adjacent radiation lines 903 have a gaptherebetween. For example, the gap may be about 0.4 μm, about 0.35 μm,about 0.3 μm, about 0.2 μm, etc.

As shown, another column 909 of individually addressable elements 904represented by hollow circles is situated at the angle θ relative to thescanning direction 901. The column 909 is similar to the column 907 buthas a small displacement in the direction perpendicular to the scanningdirection so that the radiation lines 905 generated by the column 909 ofindividually addressable elements 904 may be interleaved with theradiation lines 903 generated by the column 907 of the individuallyaddressable elements 902. Therefore, the radiation lines 905 may fillthe gaps between the adjacent radiation lines 903. As a result, theradiation lines 903 and the radiation lines 905 may collectively producea brush. In an embodiment, the displacement 906 between adjacentradiation lines is 0.4 μm, equal to the effective pitch in FIG. 7A. Inan embodiment, both column 907 and column 909 comprise 11 individuallyaddressable elements 902, 904. Considering a lens placement error of 0.5μm on both sides of the columns 907 and 909, a brush line generatedcollectively by columns 907 and 909 may have a width of about 6.8 μm.

To enable the interleaving, FIG. 9B depicts two emitter arrays 910, 915that respectively have the column 907 and the column 909. The firstemitter array 910 comprises a plurality of columns 907 stackedessentially in parallel, each column situated at an angle θ relative tothe scanning direction 901. The pitch of adjacent columns 907 is thesame as the pitch between adjacent individually addressable elements 902in column 907. In an embodiment, the pitch of adjacent columns 907 isabout 7 μm. In an embodiment, each side of the first emitter array 910is about 70 μm long so that the diagonal of the first emitter array 910is about equivalent to the field of view (about 100 μm) of the lensassociated with the first emitter array 910.

Similarly, the second emitter array 915 comprises a plurality of columns909 stacked essentially in parallel, each column is situated at an angleα relative to the scanning direction 901. The pitch of adjacent columns909 is the same as the pitch between adjacent individually addressableelements 904 in the column 909. In an embodiment, the pitch of adjacentcolumns 909 is about 7 μm. In an embodiment, each side of the secondemitter array 915 is about 70 μm so that the diagonal of the secondemitter array 915 is about equivalent to the field of view (about 100μm) of the lens associated with the second emitter array 915. The secondemitter array 915 has a small displacement in the directionperpendicular to the scanning direction relative to the first emitterarray 910. This is so that the radiation lines 903 generated by thecolumns 907 of individually addressable elements 902 in the firstemitter array 910 are interleaved with the radiation lines 905 generatedby the columns 909 of individually addressable elements 904 in thesecond emitter array 915 as described in FIG. 9A. As a result, the firstemitter array 910 and the second emitter array 915 may collectivelyproduce a brush that covers the field of view of the lens associatedwith the first emitter array 910 or with the second emitter array 915.In an embodiment, the first emitter array 910 and the second emitterarray 915 comprise eleven columns 907 of individually addressableelements 902 and eleven columns 909 of individually addressable elements904, respectively. Each column 907 may be paired with a column 909 toproduce a brush line with a width of about 6.8 μm. Therefore, a pair ofthe first emitter array 910 and the second emitter array 915 maycollectively produce a brush with a brush width of about 6.8 μm*11=74.8μm.

As will be appreciated, the interleaving need not be uniform and/or canbe provided by more than one extra emitter array.

As shown in FIG. 9C, the first emitter array 910 and the second emitterarray 915 are each associated with a lens 925, forming a firstindividual optical engine component 921 and a second individual opticalengine component 923 respectively. In an embodiment, the width (e.g.,diameter) of the lens 925 is about 1 mm, and the field of view of thelens 925 is about 100 μm. A pair 927 of a first individual opticalengine component 921 and a second individual optical engine component923 is used to produce a brush as described in FIG. 9B. A plurality ofsuch pairs 927 may be arranged as shown and form a group 920 of pairs927. The number of pairs in the group 920 is determined by, e.g., thewidth (e.g., diameter) of the lens 925; for example, so that the brushescontiguously extend to cover the width of a lens 925. In particular, ina group 920, adjacent pairs 927 have an appropriate displacement in thedirection perpendicular to the scanning direction. This is done so thatthe group 920 of pairs 927 may collectively cover an area on thesubstrate with a width equivalent to the width of the lens 925. Forexample, the group 920 may comprise 14 pairs of first individual opticalengine component 921 and second individual optical component 923. Sincea brush produced by each pair 927 has a brush width of about 75 μm, thebrushes produced by the group 920 may cover an area on the substratewith a width of about 1.05 mm, which is approximately equal to the width(e.g., 1 mm) of the lens 925.

FIG. 9D depicts an example micro-lens array (MLA) module 930, whichcomprises a plurality of groups 920 arranged as shown so that the brushproduced by the first pair 935 in a group has slight overlap with thebrush produced by the last pair 937 in the adjacent group. In this way,the brushes generated by all the groups 920 in the MLA module 930 arestitched together. The width of area on the substrate that the MLAmodule 730 is capable of covering is determined by the number of groups920 contained in the MLA module 930. In an embodiment, the MLA module930 comprises thirty groups 920 of pairs 927. As described above, eachgroup 920 of pairs 927 may cover an area with a width of about 1 mm.Therefore, the MLA module 930 may collectively produce a pattern thatcovers an area on the substrate with a width of about 30 mm. It isappreciated that the MLA module 930 may comprise a different number ofgroups 920.

FIG. 9E depicts a patterning device 940, e.g., for use in manufacturingof a flat panel display. The patterning device 940 comprises a row 939of MLA modules 930. The number of MLA modules 930 provided in a row 939is determined by, e.g., the width of the substrate 114 and the width ofthe pattern produced by each MLA module 930 if a substrate 114 isdesired to be exposed in a single pass. For example, if the substrate114 is 3 m wide, and each MLA module 930 is capable of covering an areaon the substrate with a width of 30 mm, at least 100 MLA modules 930should be provided in the row 939 of the MLA modules 930. The row 939 issituated perpendicular to the scanning direction. The pitch betweenadjacent MLA modules 930 is carefully chosen so that the patternsproduced by adjacent MLA modules 930 have slight overlaps. As a result,in an embodiment, a row 939 of MLA modules 930 collectively covers thewhole width of the substrate 114.

It should be noted that the total number of lenses required to cover anarea on the substrate with widths equivalent to the diameters of thelenses is closely related to the pitches between adjacent individuallyaddressable elements, the field of view of the lens, the lens positiontolerance, the diameter of the lens, and the required redundancy whichwill be discussed further. In other words, when the field of view of thelens (e.g., 100 μm), the lens position tolerance (e.g., 0.5 μm on eachside of the lens), the width (e.g., diameter) of the lens (e.g., 1 mm),and the required redundancy are all determined, the total number of therequired lenses is closely related to the pitch between adjacentindividually addressable elements. In an embodiment, the patterningdevice 940 comprises two or more rows 939 of MLA modules 930 stacked inparallel and aligned in the scanning direction for introduction of, forexample, redundancy, etc. as similarly described with respect to FIG.7E.

Thus, in an embodiment, direct emitter imaging is performed by writingpatterns with arrays of emitters (e.g., LEDs) coupled to an array ofmicrolenses. As discussed above, a single row of emitters essentiallyparallel to the scan direction (i.e., at the angle discussed above)defines a single brush line. Then, multiple brush lines next to eachother over the width of the field of view of a microlens form a singlebrush. So, depending on, for example, the emitter bonding pitch (inother words, how close the emitters can be placed next to each other),one or more microlenses, each microlens having individually addressableelements that project beams therethrough and having the individuallyaddressable elements stacked in the scan direction as discussed above,are employed to achieve the desired brush line width and brush width toeffectively cover the field of view of a microlens. Additionally,multiple brushes are used to fill the width of the microlens pitch, byagain stacking microlenses with emitters in the scan direction. Then,the above arrangements can be repeated in a direction perpendicular tothe scanning direction as needed to accommodate the size of thesubstrate to be exposed.

So, besides emitter bonding pitch, several design parameters put aconstraint on the number of emitters and microlenses that can be used. Afirst parameter is the field of view of a single microlens. The ratiobetween the width (e.g., diameter) of the lens and its field of viewdetermines the amount of microlenses needed to write across the width ofthe microlens pitch. Another parameter is a redundancy for the pattern,which determines a minimum amount of emitters needed per pixel. Further,optical power of a single emitter in combination with the doserequirement of the application (e.g., the amount of dose needed topattern a resist) sets a minimum amount of emitters needed per pixel.Additionally, microlens positioning error introduces a required overlapof emitter arrays and therefore influences the total amount ofmicrolenses used to write a full pattern.

So, in an embodiment, given microlenses with, for example, a width(e.g., diameter) of 1 mm and a field of view of, e.g., 70 μm, at least15 microlenses are needed to fill a 1 mm scan width corresponding to thepitch of the microlenses. For a 1 μm CD, taking into account a grayscale factor of 2.5 and a lens positioning error of 0.5 μm, to create abrush of 70 μm out of a single lens, at least 15×15 emitters arerequired in the field of view. This results in a maximum emitter pitchof about 5.0 μm (e.g., a 5.0 μm emitter bonding pitch) for a solutionwith a lowest number of lenses.

The number of lenses used scales aggressively with the emitter pitch, asshown in FIG. 10. FIG. 10 depicts the relationship between the totalnumber of lenses required to cover an area having a width equivalent tothe diameter (e.g., 1 mm) of each lens and the pitch between adjacentindividually addressable elements for a particular lens for about 0.4micron CD. The X-axis represents the pitch between adjacent individuallyaddressable elements and the Y-axis represents the total number oflenses required to cover an area with a width equivalent to that of eachlens. As shown, when the emitter pitch is between 4 μm and 5 μm, 15lenses are needed to cover an area with a 1 mm width. But, when theemitter pitch is increased (e.g., if it is not possible to provide anemitter pitch of about 5 μm, the number of the lenses needed varies asshown in FIG. 10 depending on the emitter pitch. For example, a nextdesirable emitter pitch would be about 7 μm. When the pitch is about 7μm, about 28 lenses are needed to cover the area with a 1 mm width, as,for example, shown in FIG. 9C. Further, for example, as described inFIG. 9B, where the pitches between adjacent individually addressableelements are about 7 μm, two emitter arrays 910 and 915 are provided tocollectively produce a brush covering the width of the field of view ofa lens, i.e., two lenses are used per brush. Accordingly, FIG. 9Cindicates 28 lenses 925 to cover an area on the substrate with a widthequivalent to the width (e.g., 1 mm) of each lens 925. By changing thepitch from 5 μm to 7 μm, the number of lenses to cover an area of 1 mmwidth on the substrate approximately doubles.

A patterning device (e.g., the patterning devices 740, 940) may havethousands of individually addressable elements. One or more controllersmay be provided to control these individually addressable elements(e.g., modulate these individually addressable elements “ON” and “OFF”including various gray levels in between, e.g. 8 bit addressing for 256power levels). In an embodiment, the one or more controllers may becomplementary metal-oxide semiconductor (CMOS) control circuits. Thecontrol circuits need to be connected to the individually addressableelements 102 but as will be appreciated, space is very limited. Directbump bonding is a common method for interconnecting individualsemiconductor devices to external circuitry by using solder bumps thathave been deposited onto the semiconductor device. However, a bump pitchsize is typically at least 20 μm. But, as discussed above, the size ofan individually addressable element can be only 1 μm and the pitch canbe about 5 or 7 μm, and so direct bump bonding technology may notprovide enough resolution to allow one or more control circuits tointerconnect with each individually addressable element.

FIG. 11 depicts a highly schematic top view of a portion of a patterningdevice (e.g., the patterning device 104, 740 or 940) comprising aplurality of individual optical engine components 1118. Each individualoptical engine component 1118 comprises an emitter array 1110 and a lens1115, which are similar to the emitter arrays 710, 910, 915 and thelenses 715, 925, respectively. In an embodiment, the lens 1115 has afield of view of, e.g., 100 μm (equivalent to the diagonal of theemitter array 1110) and a width of, e.g., 1 mm. Therefore, the spacing1125 between two adjacent emitter arrays 1110 is about at least 1 mm.Each individual optical engine component 1118 further comprises a bondpad area 1120 adjacent to the emitter array 1110. For example, where theemitter array 1110 is above a lens 1115, the bond pad area 1120 issimilarly above the lens 1115. In an embodiment, the bond pad area 1120is attached to the lens 1115. Although the bond pad area is a square asshown in FIG. 11, the bond pad area may have any other suitable shape,for example, a circle, a polygon, etc.

A zoom-in view of a portion 1130 of the bond pad area 1120 is depictedin FIG. 11. As shown, the portion 1130 of the bond pad area 1120includes a plurality of bonding pads 1135. Although the bonding pads1135 have square shapes as shown in FIG. 11, the bonding pads 1135 mayhave any other suitable shapes such as circle, rectangular, etc. Thesize of each bonding pad 1135 may be more than or equal to about 400 μm²and less than or equal to about 1600 μm². A bonding pad 1135 may belarger than or equal to 20 μm*20 μm, larger than or equal to 30 μm*30μm, larger than or equal to 40 μm*40 μm, etc. The bonding pad 1135enable interconnection with one or more control circuits using directbump bonding technology as mentioned above, or any other suitabletechnologies such as, for example, using bonding wires. As will beappreciated the bonding pads 1135 may be arranged all the way around theperiphery of the emitter array 1110. Thus, the bond pad area maysurround and even overlap with the emitter array 1110 (e.g., if it isproduced in a physically different layer, and can thus be stacked on topof the emitter array). The bond pad area accordingly allows for morearea to realize the bonding of all individual emitters. Because of thepitch mismatch between emitters and bonding technology, typically alarger area than the emitter array 1110 would be needed to realize thebonding.

As shown in the zoom-in view of a portion 1130 of the bond pad area 1120as depicted in FIG. 11 and as shown in FIG. 12, each of the bonding pads1135 is further connected to a corresponding individually addressableelement 1210 in the emitter array 1110 via a metal line 1137, therebyallowing for control of the individually addressable element 1210. In anembodiment, the metal lines 1137 are copper, gold or aluminum lines. Themetal lines 1137 may be produced using a conventional lithographicapparatus using, for example, a mask. The linewidth of each metal line1137 may be at least a few hundred nanometers. The metal lines 1137 arenot in contact with each other to avoid electrical problems such asshorting. Such a configuration of the bond pad area 1120, the bondingpads 1135 and the metal lines 1137 extending from the emitter array 1110and around the periphery of the emitter array 1110 can be referred to asa fan-out structure.

Various embodiments may be employed to arrange the metal lines 1137 inthe emitter array 1110. In an embodiment, all the metal lines 1137 areproduced in a single layer on the surface of the emitter array 1110 asshown in FIG. 12. In an embodiment, the pitch between adjacentindividually addressable elements 1210 is 5 μm and each of theindividually addressable elements 1210 is connected to a metal line1137. So, in an embodiment, the linewidths of the metal lines 1137 canbe 429 nm or less. A spacing of between metal lines can be 429 nm orless and the spacing between the group of metal lines and an adjacentindividually addressable element 1210 can be about 1 micron or less. Inan embodiment, between adjacent individually addressable elements 1210are at most four metal lines with an equal spacing of 429 nm.

Alternatively or in addition, the metal lines 1137 may be produced in 2or more layers on the surface of the emitter array 1110 in a manner thatany two of the metal lines 1137 do not cross with each other to avoidelectrical problems such as shorting. An advantage of this scheme isthat, e.g., wider metal lines 1137 could be produced on the surface ofthe emitter array 1110, thereby reducing the resistivity of the metallines 1137. The reduction of the resistivity of the metal lines 1137 maymitigate a plurality of related electrical problems, such as heating andelectromigration.

Linewidth roughness (LWR) can be one of the limiting factors ofstate-of-the-art lithography. LWR is the deviation of a feature shapefrom a smooth, ideal shape. It has been discovered that the effect ofLWR may be limited by the largest distance between neighboringindividually addressable elements in the emitter array. In other words,the effect of LWR may be mitigated by decreasing the maximum distancebetween neighboring individually addressable elements. However, asdiscussed above, the pitch of adjacent individually addressable elementsis determined by various factors, such as lens width, etc. Thus,mitigating LWR by decreasing the pitch in an emitter array may not bepossible. However, improved performance may be achieved by designing theemitter array according to a particular desirable configuration.

Similar to the emitter arrays 710, 910, and 915, an emitter array 1300may have a plurality of individually addressable elements 1310 arrangedin a rectangular shape as shown in FIG. 13A. As discussed above, thedimension of the emitter array should be selected to cover the field ofview of the lens associated with the emitter array. As shown in FIG.13A, the emitter array 1300 comprises six rows 1320 of individuallyaddressable elements 1310. Each row 1320 comprises six individuallyaddressable elements 1310. The pitch of the emitter array 1300 isdenoted by “p”. Therefore, an individually addressable element may havean equal distance (“p”) with an adjacent individually addressableelement in the same row or in the same column. However, a largestdistance between adjacent individually addressable elements 1310 isbetween an individually addressable element and its neighboringindividually addressable element in the diagonal direction, which isdenoted by “√2p.” In an embodiment, the emitter array 1300 can bereferred to as an emitter array with adjacent individually addressableelements arranged in a square configuration.

For comparison, in an embodiment, FIG. 13B shows an emitter array 1350with similar dimensions as the emitter array 1300. The emitter array1350 comprises seven rows of individually addressable elements. Similarto 1320, each row (i.e., R1, R2, . . . , R7) comprises six individuallyaddressable elements 1310, and the pitch between adjacent individuallyaddressable elements 1310 in the same row is denoted by “p.” Differentfrom the emitter array 1300, the emitter array 1350 is configured thatsuch that, e.g., the even rows (i.e., R2, R4, and R6) have a horizontaldisplacement 1360 of 0.5p with respect to the odd rows (i.e., R1, R3,R5, and R7). In an embodiment, the vertical displacement 1370 betweenadjacent rows is approximately 0.87p. Thus, in this configuration, thedistances between neighboring individually addressable elements 1310 inthe emitter array 1350 are all equal to p. As a result, the emitterarray 1350 may comprise a plurality of hexagonal structures 1375.Therefore, the emitter array 1350 can be referred to as an emitter arraywith adjacent individually addressable elements arranged in a hexagonalconfiguration. In an embodiment, the emitter array 1350 may be situatedat an angle θ between a column 1380 of individually addressable elements1310 and the scanning direction 1390 for relative movement between thesubstrate (e.g., the substrate 114) and the emitter array 1350.

Compared with the emitter array 1300, the maximum distance between theneighboring individually addressable elements in emitter array 1350 isdecreased from √2p (as in FIG. 13A) to p (as in FIG. 13B). Therefore,the LWR effect may be mitigated by a factor of √2. For example, when theemitter array 1350 is arranged at angle θ, the effective pitch isincreased from 0.4 μm to 0.4√2 μm (i.e., 0.57 μm) for 1 μm CD. Further,a reduction can be achieved in the gray scale factor for a squareconfiguration emitter array, which is determined based on, among otherthings, the largest distance neighbor to an individually addressableelement to account for worst case LWR. Thus, the gray scale factor canbe decreased from 2.5 to 2.5/√2 (i.e., 1.77).

In an embodiment, the emitter array 1350 has a higher density ofindividually addressable elements 1310 per lens than the emitter array1300 at the same minimum pitch. Advantageously, this can reduce cost.

From another perspective, the pitch of the emitter array 1350 may beincreased while keeping the density of individually addressable elements1310 in the emitter array 1350 the same as the density of individuallyaddressable elements 1310 in the emitter array 1300. Advantageously, thelarger pitch induces less technological risk, e.g., with bonding asdescribed above.

Thus, the hexagonal configuration can yield significant reduction inrequired number of emitters per unit area at constant imagingperformance (excluding dose limitations per emitter), as well as apacking density gain versus the square configuration. Furthermore, thedata path scales with the number of individually addressable elementsand so the hexagonal configuration can yield, e.g., less complexity andreduced cost. Further, line width roughness can be improved with ahexagonal configuration at a same number of individually addressableelements per area compared to the square configuration.

The hexagonal configuration can also be extended to other elements. Forexample, the microlenses can be arranged in hexagonal configuration in aMLA. In another example, MLA modules can be arranged in hexagonalconfiguration.

In an embodiment, there is some focus dependency in the formation offeatures (e.g. their profile changes as a function of focus) and sofocus control is provided by changing, e.g., changing a focal length,adjusting the relative position between the substrate and a focal pointor range, etc. Among various parameters that can characterize the focusdependency in the formation of the features, depth of focus (DOF)parameter specifies the range of focus that can be tolerated before thequality of the features printed on the substrate become too degraded.For example, the expected DOF of a patterning device (e.g., thepatterning device 104, 740 or 940) as described herein for flat paneldisplay applications can be in the range of 3-5 μm. This indicates thatfeatures are not able to be printed well on a substrate where, forexample, a distance of a portion of the substrate from a nominal planeof the substrate (hereinafter referred to as height variation of thesubstrate for convenience) is beyond the DOF selected from the range of,for example, 3-5 μm, without focus control. But, for a flat paneldisplay application as an example, the substrate can exhibit up to 12 μmheight variation over a distance of 150 mm on the substrate, which isfar beyond the DOF described above. Therefore, local focus control ofthe patterning device (e.g., the patterning device 104, 740, or 940)with respect to the substrate is desired. A possible solution isadjusting the relative position between each individually addressableelement in the patterning device and the substrate in a directionsubstantially orthogonal to the substrate (hereinafter referred to asheight for convenience) using one or more actuators. This, for example,may not be cost effective due to the requirement of a large amount ofactuators for implementing this solution. Moreover, with a small pitchof emitters, it may not be practical to implement focus control for eachemitter independently.

So, in an embodiment, instead of adjusting the heights and/or tilts ofeach individually addressable element, one or more high precisionactuators may be used to adjust the heights and/or tilts of a pluralityof individually addressable elements collectively in a MLA module (e.g.,the MLA modules 730 and 930). The dimensions of the MLA module in theplane orthogonal to the height direction are determined such that themaximum height variation of the substrate corresponding to the size ofthe MLA module is within the DOF. For example, the dimensions of a MLAmodule may be 10 mm*10 mm (specifically of the microlens array adjacentthe substrate). Given a substrate height variation of 80 nm per lateralmm, a maximum height variation of the corresponding substrate is 10mm*80 nm/mm=0.8 μm, which is well below the DOF of 3-5 μm. So, byoperating one or more actuators to adjust the height and/or tilt of theindividually addressable elements collectively relative to the substrate(e.g., within 20 μm with 0.5 μm precision), the relative positionbetween the focus of the individually addressable elements of the MLAand the substrate can be precisely controlled within the DOF. Of course,the MLA module may have other suitable dimensions as long as the maximumheight variation of the corresponding portion of the substrate is withinthe DOF. Further, since the patterning device may comprise a pluralityof such MLA modules (e.g., 500-2500 MLA modules), the focus for thepatterning device can be controlled within the DOF by preciselycontrolling each MLA module of the patterning device using the methoddescribed herein, e.g., one or more MLA modules can be controlledindependently of one or more other MLA modules.

Additionally or alternatively to addressing focus, alignment between MLAmodules may also need to corrected. That is, for example, one or moreMLA modules may not be properly aligned (e.g., at initial setup or overtime) relative to one or more other MLA modules. Accordingly, the one ormore high precision actuators may be used to adjust the position in Xand/or Y directions of a MLA module relative to another MLA module.

Referring to FIG. 14, a highly schematic view of a disassembled MLAmodule 1400 is depicted. The MLA module 1400 may be similar to the MLAmodules 730 and 930. The MLA module 1400 comprises a microlens array(MLA) 1470, an electronics board 1460, and a structure 1420.

As shown, the MLA 1470 comprises a plurality of lenses 1480 arranged ina square array (of course, a different arrangement may be provided). Inan embodiment, each lens 1480 has a width (e.g., diameter) of 1 mm. Eachlens 1480 is configured to project beams from an associated emitterarray 1465 to the substrate (not shown).

A plurality of emitter arrays 1465 is located on a (bottom) surface ofthe electronics board 1460. In an embodiment, the number of lenses 1480equals the number of emitter arrays 1465. Each emitter array 1465comprises a plurality of individually addressable elements as describedabove. In an embodiment, the individually addressable elements are LEDs.In an embodiment, the MLA 1470 is attached to the plurality of emitterarrays 1465, e.g., attached to the electronics board 1460.

One or more high precision actuators 1455 are located between theelectronics board 1460 and the structure 1420. As shown in FIG. 14, fouractuators 1455, for example, are located at the corners of theelectronics board 1460; in an embodiment, less or more actuators may beprovided and provided at one or more different locations (e.g., anactuator may be located in a central portion). The one or more actuators1455 have a tuning range of, e.g., 20 μm with 0.5 μm precision. Bytuning the one or more actuators 1455, the focuses of the plurality ofemitter arrays 1465 and the associated lenses of the MLA 1470 may becollectively adjusted accordingly. For example, the one or moreactuators 1455 can move the plurality of emitter arrays 1465 and theassociated lenses of the MLA 1470 in the Z direction shown to, forexample, enable focus adjustment. Further, in an embodiment, the one ormore actuators 1455 can additionally or alternatively, move theplurality of emitter arrays 1465 and the associated lenses of the MLA1470 around the X and/or Y directions shown to, for example, enablefocus adjustment. Further, in an embodiment, the one or more actuators1455 can additionally or alternatively, move the plurality of emitterarrays 1465 and the associated lenses of the MLA 1470 in the X and/or Ydirections shown to enable, e.g., alignment of the plurality of emitterarrays 1465 and the associated lenses of the MLA 1470 relative toanother plurality of emitter arrays and associated lenses of anotherMLA. While the structure 1420 is shown as covering the electronics board1460, it need not do so.

In an embodiment, the electronics board 1460 further comprises aplurality of local memories 1430 and a local processing unit 1450. In anembodiment, the local memories 1430 are configured to store the datapathsignals (or other control signals) which cause the local processing unit1450 to control each individually addressable elements of the pluralityof emitter arrays 1465 in the MLA module 1400 (e.g., turning “ON” or“OFF” each individually addressable element). Certain control signalsmay cause the local processing unit 1450 to automatically tune the oneor more actuators 1455 to control the focuses of the MLA module 1400and/or the alignment of the MLA module 1400 relative to another MLAmodule.

The structure 1420 is coupled to the electronics board 1460 via the oneor more actuators 1455. In an embodiment, the structure 1420 comprisesan interface 1410 configured to couple the datapath signals or othercontrol signals from one or more external controllers to the localprocessing unit 1450 and/or the one or more actuators 1455. In anembodiment, the interface 1410 is further configured to couple the localprocessing unit 1450 and/or the individually addressable elements and/orthe one or more actuators 1455 to an external power source (not shown),which provides electrical power to the processing unit 1450 and/or theindividually addressable elements and/or the one or more actuators 1455.

Further, the description herein has primarily focused on exposing aradiation-sensitive surface of a substrate. In appropriatecircumstances, new processes may be adopted to eliminate one or moreproduction steps or substitute one or more production steps with one ormore other production steps to lead to a production process that isquicker and/or more efficient, etc. As an example, the production of aflat panel display traditionally involves production of a number oflayers using photolithography, deposition and etching. In a morespecific example, production of a backplane for a flat panel display mayinvolve the creation of 5 layers, each involving photolithography,deposition and etching. Such production may involve 5 process steps andoften 5 tools to define a metal pattern. The steps include metal sheetdeposition, photo resist coating, photolithography and developing of theresist, etching of the metal using the developed resist, and strippingof the resist after etching. Thus, not only is there a significantamount of capital (e.g., in the form of tools) and time required, thereis also a significant amount of material usage. For example in definingan active matrix flat panel display, photoresist may be used to cover a3 m×3 m glass plate, which photoresist is later completely washed away.Similarly, copper and/or other metals are deposited on the full glassplate and later up to 95% of which is washed away. Further, chemicalsare used to etch or strip the above materials.

Thus, improvement of such production could be achieved by consolidatingone or more reductive steps into an additive step. Thus, rather than acombination of photolithography, deposition and etching steps, amaterial deposition step may be used to deposit a layer of material onthe substrate. In an embodiment, the material may be aluminum, chromium,molybdenum, copper, gold, silver, titanium, platinum or any combinationselected therefrom.

In an embodiment, the layer of material is deposited on the substrate asnanoparticles. That is, in an embodiment, a stream of nanoparticles isprovided to a substrate to form a layer of material on the substrate.After the nanoparticles are deposited on the substrate, a pattern isproduced by sintering at least a portion of the nanoparticles accordingto the desired pattern using, for example, one or more patterningradiation beams, such as a plurality of beams provided by the apparatusdescribed herein or by a patterned beam produced by a traditionalmask/reticle-based lithography apparatus.

Direct material deposition in the form of nanoparticles in combinationwith patterning could eliminate several reductive process stepstypically used, for example, in flat panel display manufacture.Additionally and alternatively, ablation of a deposited layer ofmaterial may be used to eliminate material without, for example, theneed for resist coating and developing. Consequently, direct materialdeposition can be a natural extension of lithography, where radiationbeam energy is used to process or pattern a material by, e.g.,sintering, ablation, etc.

Accordingly, it is desirable to produce a layer of material usingsubstantially stable nanoparticles so that the layer can be used in apatterning process (e.g., sintering, ablation, etc.). Creating such alayer can be challenging. For example, the nanoparticles should havesmall sizes, e.g., below 15 nm width (e.g., diameter) in order to beeffectively sintered. However, small nanoparticles have a tendency toaggregate when provided to a surface, thereby making them unstable orunsuitable. A potential solution to help prevent small nanoparticlesfrom aggregating into larger particles involves coating thenanoparticles with one or more additives (e.g., a resist-like polymer).However, contamination (i.e., the additive) can be introduced to thesubstrate and/or system and be hard to remove completely after thepatterning process.

In an embodiment, for example, a single apparatus may be used for most,if not all, layers of a substrate (e.g., flat panel display production).For example, the apparatus may perform generation and deposition ofsmall nanoparticles (e.g., below 15 nm) on the substrate. The apparatusmay further perform patterning of the layer of nanoparticles by, e.g.,sintering at least a portion of the nanoparticles.

FIG. 15 depicts a highly schematic top view of a patterning apparatus1500 according to an embodiment for exposing substrates in themanufacture of, for instance, flat panel displays (e.g., LCDs, OLEDdisplays, etc.). The patterning apparatus 1500 comprises a substratetable 1506 to hold a substrate 1514 (e.g., a flat panel displaysubstrate) and a positioning device 1516 to move the substrate table1506 in up to 6 degrees of freedom.

The patterning apparatus 1500 further comprises a patterning module 1540and one or more nanoparticle generators 1520 on a frame 1560. In anembodiment, the patterning module 1540 comprises a plurality ofindividually addressable elements (which may be similar to thepatterning devices 740 and 940) and optionally include one or moreprojection optics. In an embodiment, the individually addressableelements are radiation emitting diodes, e.g., LEDs. In an embodiment,the patterning module 1540 may comprise a holder for mask/reticle andprojection optics to project a beam patterned by the mask/reticle to thesubstrate 1514. In an embodiment, the patterning module 1540 issubstantially stationary, i.e., it does do not move significantly duringprojection.

The one or more nanoparticle generators 1520 are configured to generatesmall nanoparticles (e.g., below 15 nm) and deposit a layer ofnanoparticles on the substrate 1514. In an embodiment, the layer ofnanoparticles is deposited during a relative motion between thenanoparticle generators 1520 and the substrate 1514 (e.g., during amotion of the substrate 1514 in direction 1510). The one or morenanoparticle generators 1520, or a portion thereof, may be moved in upto six degrees of freedom (e.g., in Z, rotation around X, and/orrotation around Y) using one or more actuators to, for example, enablecoverage of the substrate 1514. Three nanoparticle generators 1520 areshown in FIG. 15. However, another suitable number of nanoparticlegenerators 1520 may be used. The number of nanoparticle generators 1520is determined by the width of the substrate 1530 and the coverage ofarea on the surface of the substrate 1514 by each nanoparticle generator1520. For example, if a layer of particles is deposited in a single passof the substrate 1514 in direction 1510, at least three nanoparticlegenerators may be required if the covering range of each nanoparticlegenerator 1520 is limited to a third of the substrate width 1530.Optionally, the number of nanoparticle generators 1520 in the patterningapparatus 1500 may further be determined by the speed by which eachnanoparticle generator 1520 generates nanoparticles (i.e., how manynanoparticles can be generated by each nanoparticle generator 1520 in aunit period of time, e.g., a minute, an hour, etc.). In some examples,the speed of generating nanoparticles by each nanoparticle generator1520 is relatively slow compared to, for example, the speed of relativemovement. Therefore, increasing the number of nanoparticle generators1520 may be necessary to reduce the time needed to deposit a layer ofnanoparticles on the surface of the substrate 1514.

In an embodiment, the position on the substrate 1514 where thenanoparticles are deposited by a nanoparticle generator 1520 may becontrolled mechanically, for example, by means of gas. For example, astream of gas may carry a plurality of nanoparticles onto an area of thesubstrate 1514 in the path of the traveling direction of the gas. Byvarying the traveling direction of the gas (e.g., by raster scanning thesubstrate 1514 and/or by moving at least part of a nanoparticlegenerator 1520), a layer of nanoparticles may be accurately deposited ondifferent areas of the substrate within the coverage range of thenanoparticle generator 1520. Further, overlap of adjacently depositedportions of the layer of nanoparticles generated by a plurality ofnanoparticle generators 1520 may be avoided by accurately controllingthe traveling direction of the respective streams of gas.

Alternatively or additionally, the position on the substrate 1514 wherethe nanoparticles are deposited by a nanoparticle generator 1520 may becontrolled by means of an electro-magnetic field surrounding a stream ofthe nanoparticles, e.g., using one or more electro-magnetic lenses. Anelectro-magnetic lens comprises a coil of wire (e.g., copper wire)through which current flows. By appropriately changing the currentflowing inside the coil, the electro-magnetic lens may provide a varyingelectro-magnetic field, which allows for manipulation of the directionof flow of the nanoparticles to e.g., raster scan an area of thesubstrate 1514. Overlap of adjacently deposited portions of the layer ofnanoparticles generated by a plurality of nanoparticle generators 1520may be avoided by accurately controlling the traveling direction of therespective streams of nanoparticles by controlling electromagneticfields using one or more electro-magnetic lenses.

The patterning apparatus 1540 may further comprise an alignment sensor(not shown in FIG. 15) to determine alignment between the patterningmodule 1540 and the substrate 1514, and a level sensor (not shown inFIG. 15) to determine whether the substrate 1514 is level with respectto the patterning performed by the patterning module 1540.

In operation of the patterning apparatus 1500, a substrate 1514 isloaded onto the substrate table 1506 using, for example, a robot handler(not shown). The substrate 1514 is then displaced in the direction 1510under the frame 1560. A layer of nanoparticles is deposited on thesurface of the substrate 1514 using the one or more nanoparticlegenerators 1520. Optionally, the substrate 1514 is measured by the levelsensor (not shown) and/or the alignment sensor (not shown). Afterdeposition of the layer, the layer of nanoparticles is patterned by thepatterning module 1540. In an embodiment, the patterning module 1540exposes the layer of nanoparticles to one or more beams of radiation tocreate the pattern. In an embodiment, the one or more beams sinter apattern into the layer of nanoparticles, where the sintering maycomprise one step of sintering the nanoparticles sufficiently to stablyform the pattern or may comprise multiple steps of sintering thenanoparticles where a first step forms the pattern (e.g., fixes thepattern using the radiation beam) but not highly stably and then one ormore further steps form the pattern stably (e.g., using the radiationbeam again). In an embodiment, the one or more beams ablate a patterninto the layer of nanoparticles. In an embodiment, the radiation beamsare provided by individually addressable elements of a patterning device(e.g., the patterning device 104, 740, or 740) within the patterningmodule 1540. In an embodiment, the individually addressable elements 102of a patterning module 1540 may be operated as turned “ON” or “OFF” toemit radiation beams on the layer of nanoparticles to, for example,sinter at least a portion of the nanoparticles on the substrate (using,for example, pixel-grid imaging as described above). In an embodiment,the deposition and patterning occur in a continuous motion in thedirection 1510.

More details about an embodiment of a nanoparticle generator 1520 arenow described in relation to FIG. 16. Referring to FIG. 16, a highlyschematic cross-section of a nanoparticle generator 1520 is depicted.FIG. 16 depicts an embodiment of the physical mechanism of generationand streaming of nanoparticles using the nanoparticle generator 1520.The nanoparticle generator 1520 comprises a first electrode 1610 and asecond electrode 1620 (i.e., one is an anode, and the other is acathode). In an embodiment, both the first electrode 1610 and the secondelectrode 120 are made of aluminum, chromium, molybdenum, copper, gold,silver, titanium, platinum, or any combination selected therefrom. Thefirst electrode 1610 and the second electrode 1620 are made of the samematerial or different materials. Further, the first electrode 1610 andthe second electrode 1620 may have any suitable shape. For example, asshown in FIG. 16, both the first electrode 1610 and the second electrode1620 are hollow cylinders.

In an embodiment, the nanoparticle generator 1520 is in vacuum or isprovided with a flow of gas 1640 (provided from an outlet ofnanoparticle generator 1520), such as nitrogen (N₂), helium (He), neon(Ne), argon (Ar), Krypton (Kr), xenon (Xe), radon (Rn) or a combinationselected therefrom. Desirably, the nanoparticles are produced andprovided in a substantially oxygen-free environment so as to limit orprevent the nanoparticles from being oxidized. For example, theenvironment inside the nanoparticle generator 1520 may be substantiallyoxygen-free.

In an embodiment, a voltage is applied between the first electrode 1610and the second electrode 1620 to generate a spark at an intensity thatcreates plasma 1630 between the first electrode 1610 and the secondelectrode 1620. The plasma 1630 ionizes the material of the firstelectrode 1610, the material of the second electrode 1620, or both, andforms a plurality of very small nanoparticles 1650. For example, thesesmall nanoparticles have sizes of 0.2 nm, 0.5 nm, 1 nm, etc. Thenanoparticles are further moved toward and onto the substrate (with orwithout the aid of gravity). Due to the small sizes, these nanoparticles1650 tend cluster with adjacent nanoparticles 1650, thereby forminglarger nanoparticles 1660. When the nanoparticles have a predeterminedsize (e.g., less than or equal to 10 nm or less than or equal to 15 nm)or range of sizes (e.g., within the range of 5-20 nm or the range of5-15 nm), the nanoparticles 1680 may be diluted by a gas 1670 (providedfrom an outlet of nanoparticle generator 1520) so that formation oflarger nanoparticles is limited or prevented. The location of theinsertion of the gas, the type of gas, and the amount of gas providedcan be determined by experiment. Optionally, a sensor system may be usedto control the location of the insertion of the gas and/or the amount ofgas. The nanoparticles 1680 with the desirable size or range of size arethen deposited on the substrate. The position where the nanoparticles1680 are deposited on the substrate may be controlled by means of gasflow (e.g., the flow of gas 1670 and/or a flow of gas 1640) and/or by anelectromagnetic field as discussed above.

In an embodiment, the layer of nanoparticles are sintered at atemperature below or equal to 200° C., or below or equal to 100° C., byusing a layer of relatively small nanoparticles (e.g., less than orequal to 10 nm or less than or equal to 15 nm in width) and providingone or more radiation beams to sinter the layer to form a pattern in thelayer of nanoparticles. The particles not sintered can be washed away.

Thus, in an embodiment, there is provided production of nanoparticlesfrom bulk material (e.g. metal or other material) directly inside thepatterning tool. In an embodiment, there is provided direct patterningof organic-free nanoparticles and/or direct patterning of sub-50 nm,desirably sub-20 nm or sub-15 nm, or sub-10 nm, nanoparticles.

In an embodiment, the nanoparticles for patterning are generated in theapparatus that applies a pattern to a layer of the nanoparticles.

In an embodiment, the nanoparticles are provided by a spark dischargegenerator (SDG) which directs nanoparticles toward a substrate fordeposit on the substrate. An embodiment of a spark discharge generatorwas described above in respect of FIG. 16. The SDG can provide sub-15 nmdiameter nanoparticles. The SDG can, e.g., provide monodispersenanoparticles, provide high-quality deposition, prevent possibleoxidation (if using, e.g., copper nanoparticles) if it has a controlledenvironment (e.g., Ar gas/N₂ gas/vacuum), and provide aggregation ofvery small particles into nanoparticles. Charged aerosols havingparticles of a size of 10 nm or less tend to cause electrostaticaggregation of bipolar nanoparticles so, in an embodiment, steps asdiscussed above are used to help prevent such aggregation intonanoparticles exceeding a desired size. For example, to reduce theaggregation, one or more operational parameters such as spark frequency,spark energy, and/or carrier gas flow, are set appropriately.

In an embodiment, multiple nanoparticle generators (e.g., SDGs) areprovided to cover a relatively large substrate area. In an embodiment,the number of nanoparticle generators comprises between 3 and 1000.

In an embodiment, as noted above, a controlled environment is applied toone or more SDGs to limit or prevent oxidation (where, for example,copper nanoparticles are used). A controlled environment allows, forexample, high quality sintered metallic features to be produced bypreventing or limiting oxidation.

In an embodiment, essentially solvent-free/organic-free nanoparticles ofa low diameter (less than or equal to 15 nm diameter) are provided. Thiscan allow, for example, high conductive metallic features to be producedby radiation beam sintering. In an embodiment, the sintering can be doneby a low power radiation (e.g., laser) beam. In an embodiment, thesintering can be done at a low temperature (e.g., less than or equal to200° C., or below or equal to 100° C.). In an embodiment, the use ofessentially solvent-free/organic-free nanoparticles of a low diameter(less than or equal to 15 nm diameter) can enable less processing stepsto realize a device, such elimination of one or more lithography steps,one or more resist development step and/or one or more etching steps.

Through having an in-situ particle generator in a patterning apparatus,stable small nanoparticles can be positioned directly on a substratewith little to no undesirable agglomeration and no transport neededafter they have been created. Further, nanoparticles can be created withlittle or no additives yielding good material quality. Further,environmental control can be provided within the particle generator orin the system in general to help ensure little or no materialdegradation. Further, in an embodiment, the thickness of the layer ofparticles can be well controlled using a tunable nanoparticle generator.

In an embodiment, several layers of different materials can be providedto the substrate by using a particle generator as described herein. Forexample, one or more particle generators may provide a first materialand one or more other particle generator may provide a second differentmaterial. Further, a particle generator may configured to alter thematerial from which particles are generated by, for example, changing toan anode or cathode of different material, by tuning either of the anodeor cathode to produce particles, etc.

In an embodiment, a controller is provided to control the individuallyaddressable elements 102 and/or patterning device 104. For example, inan example where the individually addressable elements are radiationemitting devices, the controller may control when the individuallyaddressable elements are turned “ON” or “OFF” and enable high frequencymodulation of the individually addressable elements. The controller maycontrol the power of the radiation emitted by one or more of theindividually addressable elements. The controller may modulate theintensity of radiation emitted by one or more of the individuallyaddressable elements. The controller may control/adjust intensityuniformity across all or part of an array of individually addressableelements. The controller may adjust the radiation output of theindividually addressable elements to correct for imaging errors, e.g.,etendue and optical aberrations (e.g., coma, astigmatism, etc.).

In an embodiment, patterning the radiation may be effected bycontrolling the patterning device 104 such that the radiation that istransmitted to an area of the resist layer on the substrate within thedesired feature is at a sufficiently high intensity that the areareceives a dose of radiation above the dose threshold during theexposure, whereas other areas on the substrate receive a radiation dosebelow the dose threshold by providing a zero or significantly lowerradiation intensity.

In practice, the radiation dose at the edges of the desired feature maynot abruptly change from a given maximum dose to zero dose even if setto provide the maximum radiation intensity on one side of the featureboundary and the minimum radiation intensity on the other side. Instead,due to diffractive effects, the level of the radiation dose may drop offacross a transition zone. The position of the boundary of the desiredfeature ultimately formed after developing the resist is then determinedby the position at which the received dose drops below the radiationdose threshold. The profile of the drop-off of radiation dose across thetransition zone, and hence the precise position of the feature boundary,can be controlled more precisely by providing radiation to points on thesubstrate that are on or near the feature boundary not only to maximumor minimum intensity levels but also to intensity levels between themaximum and minimum intensity levels. This is commonly referred to as“grayscaling” or “grayleveling”.

Grayscaling may provide greater control of the position of the featureboundaries than is possible in a lithography system in which theradiation intensity provided to the substrate can only be set to twovalues (namely just a maximum value and a minimum value). In anembodiment, at least three different radiation intensity values can beprojected, e.g. at least 4 radiation intensity values, at least 8radiation intensity values, at least 16 radiation intensity values, atleast 32 radiation intensity values, at least 64 radiation intensityvalues, at least 100 radiation intensity values, at least 128 radiationintensity values, or at least 256 radiation intensity values. If thepatterning device is a radiation source itself (e.g. an array of lightemitting diodes or laser diodes), grayscaling may be effected, e.g., bycontrolling the intensity levels of the radiation being transmitted. Ifthe patterning device include a deflector, grayscaling may be effected,e.g., by controlling the tilting angles of the deflector. Also,grayscaling may be effected by grouping a plurality of programmableelements and/or deflectors and controlling the number of elements and/ordeflectors within the group that are switched on or off at a given time.

In one example, the patterning device may have a series of statesincluding: (a) a black state in which radiation provided is a minimum,or even a zero contribution to the intensity distribution of itscorresponding pixel; (b) a whitest state in which the radiation providedmakes a maximum contribution; and (c) a plurality of states in betweenin which the radiation provided makes intermediate contributions. Thestates are divided into a normal set, used for normal beampatterning/printing, and a compensation set, used for compensating forthe effects of defective elements. The normal set comprises the blackstate and a first group of the intermediate states. This first groupwill be described as gray states, and they are selectable to provideprogressively increasing contributions to corresponding pixel intensityfrom the minimum black value up to a certain normal maximum. Thecompensation set comprises the remaining, second group of intermediatestates together with the whitest state. This second group ofintermediate states will be described as white states, and they areselectable to provide contributions greater than the normal maximum,progressively increasing up to the true maximum corresponding to thewhitest state. Although the second group of intermediate states isdescribed as white states, it will be appreciated that this is simply tofacilitate the distinction between the normal and compensatory exposuresteps. The entire plurality of states could alternatively be describedas a sequence of gray states, between black and white, selectable toenable grayscale printing.

It should be appreciated that grayscaling may be used for additional oralternative purposes to that described above. For example, theprocessing of the substrate after the exposure may be tuned such thatthere are more than two potential responses of regions of the substrate,dependent on received radiation dose level. For example, a portion ofthe substrate receiving a radiation dose below a first thresholdresponds in a first manner; a portion of the substrate receiving aradiation dose above the first threshold but below a second thresholdresponds in a second manner; and a portion of the substrate receiving aradiation dose above the second threshold responds in a third manner.Accordingly, grayscaling may be used to provide a radiation dose profileacross the substrate having more than two desired dose levels. In anembodiment, the radiation dose profile has at least 2 desired doselevels, e.g. at least 3 desired radiation dose levels, at least 4desired radiation dose levels, at least 6 desired radiation dose levelsor at least 8 desired radiation dose levels.

It should further be appreciated that the radiation dose profile may becontrolled by methods other than by merely controlling the intensity ofthe radiation received at each point, as described above. For example,the radiation dose received by each point may alternatively oradditionally be controlled by controlling the duration of the exposureof said point. As a further example, each point may potentially receiveradiation in a plurality of successive exposures. The radiation dosereceived by each point may, therefore, be alternatively or additionallycontrolled by exposing said point using a selected subset of saidplurality of successive exposures.

Further, while the discussion above regarding gray scaling focused onphotolithography, similar concepts may be applied to the materialdeposition discussed herein. For example, power levels and/or flow ratesmay be controlled to provide gray scaling associated with the materialdeposition.

In order to form the pattern on the substrate, it is necessary to setthe patterning device to the requisite state at each stage during theexposure process. Therefore control signals, representing the requisitestates, must be transmitted to the patterning device. Desirably, thelithographic apparatus includes a controller that generates the controlsignals. The pattern to be formed on the substrate may be provided tothe lithographic apparatus in a vector-defined format e.g., GDSII. Inorder to convert the design information into the control signals, thecontroller includes one or more data manipulation devices, eachconfigured to perform a processing step on a data stream that representsthe pattern. The data manipulation devices may collectively be referredto as the “datapath”.

The data manipulation devices of the datapath may be configured toperform one or more of the following functions: converting vector-baseddesign information into bitmap pattern data (and then to a requiredradiation dose map (namely a required radiation dose profile across thesubstrate)) or to the required radiation dose map; converting a requiredradiation dose map into required radiation intensity values for eachindividually addressable element; and converting the required radiationintensity values for each individually addressable element intocorresponding control signals.

In an embodiment, the control signals may be supplied to theindividually addressable elements 102 and/or one or more other devices(e.g., a sensor) by wired or wireless communication. Further, signalsfrom the individually addressable elements 102 and/or from one or moreother devices (e.g., a sensor) may be communicated to the controller. Ina similar manner to the control signals, power may be supplied to theindividually addressable elements 102 or one or more other devices(e.g., a deflector and/or sensor) by wired or wireless means. Forexample, in a wired embodiment, power may be supplied by one or morelines, whether the same as the ones that carry the signals or different.A sliding contact arrangement may be provided to transmit power. In awireless embodiment, power may be delivered by RF coupling.

While the previous discussion focused on the control signals supplied tothe individually addressable elements 102 and/or one or more otherdevices (e.g., a deflector and/or a sensor), they should be understoodto encompass in addition or alternatively, through appropriateconfiguration, transmission of signals from the individually addressableelements 102 and/or from one or more other devices (e.g., a sensor) tothe controller. So, communication may be one-way (e.g., only to or fromthe individually addressable elements 102 and/or one or more otherdevices (e.g., a sensor)) or two-way (i.e., from and to the individuallyaddressable elements 102 and/or one or more other devices (e.g., asensor)).

In an embodiment, the control signals to provide the pattern may bealtered to account for factors that may influence the proper supplyand/or realization of the pattern on the substrate. For example, acorrection may be applied to the control signals to account for theheating of one or more of the individually addressable elements 102,lenses, etc. Such heating may cause changed pointing direction of theindividually addressable elements 102, lenses, etc., change inuniformity of the radiation, etc. In an embodiment, a measuredtemperature and/or expansion/contraction associated with an individuallyaddressable element 102 and/or other element from, e.g., a sensor may beused to alter the control signals that would have been otherwiseprovided to form the pattern. So, for example, during exposure, thetemperature of the individually addressable elements 102 may vary, thevariance causing a change of the projected pattern that would beprovided at a single constant temperature. Accordingly, the controlsignals may be altered to account for such variance. Similarly, in anembodiment, results from the alignment sensor and/or the level sensor150 may be used to alter the pattern provided by the individuallyaddressable elements 102. The pattern may be altered to correct, forexample, distortion, which may arise from, e.g., optics (if any) betweenthe individually addressable elements 102 and the substrate 114,irregularities in the positioning of the substrate 114, unevenness ofthe substrate 114, etc.

In an embodiment, the change in the control signals may be determinedbased on theory of the physical/optical results on the desired patternarising from the measured parameter (e.g., measured temperature,measured distance by a level sensor, etc.). In an embodiment, the changein the control signals may be determined based on an experimental orempirical model of the physical/optical results on the desired patternarising from the measured parameter. In an embodiment, the change of thecontrol signals may be applied in a feedforward and/or feedback manner.

In an embodiment, the lithographic apparatus may comprise a sensor 118to measure a characteristic of the radiation that is or to betransmitted toward the substrate by one or more individually addressableelements 102. Such a sensor may be a spot sensor or a transmission imagesensor. The sensor may be used to, for example, determine the intensityof radiation from an individually addressable element 102, uniformity ofradiation from an individually addressable element 102, across-sectional size or area of the spot of radiation from anindividually addressable element 102, and/or the location (in the X-Yplane) of the spot of radiation from an individually addressable element102.

As described in FIGS. 7E and 9E, each of the patterning devices 740, 940comprises one or more rows 735, 935 of MLA modules 730, 930. In anembodiment, the MLA modules 730, 930 in each row 735, 935 are arrangedsuch that the patterns produced by adjacent MLA modules 730, 930 have aslight overlap. This is done so that the patterns produced by each row735, 935 of the MLA modules 730, 930 may collectively cover the wholewidth of the substrate 114. However, this is not always necessary. Forexample, two or more rows of the MLA modules (e.g., the MLA modules 730,930) may be used collectively as a group to produce continuous patternsthat can cover the whole width of the substrate 114.

Referring to FIG. 17, a schematic top view of a patterning device 1700is depicted, e.g., for manufacturing of a flat panel display. Thepatterning device 1700 comprises a group 1720 of MLA modules 1730. TheMLA modules 1730 are similar to the MLA modules 730 or MLA modules 930.As shown, the group 1720 of MLA modules 1730 comprises a first row(“R₁”) of MLA modules 1730 and a second row (“R₂”) of MLA modules 1730.The number of MLA modules 1730 provided in the first row, R₁ and thesecond row, R₂ are determined by the width of the substrate 114 and thewidth of the pattern produced by each MLA module 1730. In an embodiment,the first row, R₁ may include a same number of MLA modules 1730 as thesecond row, R₂. In an embodiment, the first row, R₁ may have a differentnumber of MLA modules 1730 as the second row, R₂. For example, the firstrow, R₁ may have one more or one fewer MLA module 1730 than the secondrow, R₂. In an embodiment, the spacing 1750 between adjacent MLA modules1730 in the first row, R₁ and the second row, R₂ is no greater than thewidth 1740 of the MLA module 1730 along a direction perpendicular to thescanning direction 1710 of relative movement between the substrate (notshown in FIG. 17 for convenience but would be above or below thepatterning device 1700) and the patterning device 1700. Further, thereis a lateral displacement between the first row, R₁, and the second row,R₂ so that the patterns produced by the MLA modules 1730 in the secondrow, R₂ may interleave with the patterns produced by the MLA modules1730 in the first row R₁. As a result, the first row, R₁ of the MLAmodules 1730 and the second row, R₂ of the MLA modules 1730, maycollectively produce continuous patterns, which cover the whole width ofthe substrate. As described above, although the group 1720 includes tworows (i.e., R₁ and R₂) of MLA modules 1730 as shown in FIG. 17, thegroup 1720 may include three or more rows of MLA modules 1730 in otherexamples. Accordingly, for an example of three rows, the spacing 1750between adjacent MLA modules 1730 in each row may be less than twicetimes the widths 1740 of the MLA module 1730 along the X direction sothat the three rows of MLA modules may collectively produce continuouspatterns on the substrate that covers the whole width of the substrate.

In an embodiment, as shown in FIG. 17, the patterning device 1700 maycomprise one or more further identical groups 1720 of MLA modules 1730stacked in essentially parallel fashion and aligned in the scanningdirection (i.e., the Y direction) for introduction of, for example,imaging (e.g., spacing 1750 may be expanded through the addition offurther groups 1720 of MLA modules), redundancy, etc. as similarlydescribed with respect to FIG. 7E.

During the patterning process, the optical lenses (e.g., the opticallenses 124, 1480) of a projection system may be contaminated by materialdue to, e.g., the evaporation, breaking, outgassing, etc. of photoresiston the substrate (e.g., the substrate 114), particularly when thephotoresist layer on the substrate is thick and/or the working distances(i.e., the distances between the optical lenses and the photoresistlayer during the exposure process) of the patterning system (e.g., thelithographic projection apparatus 100) are short. The contaminationproblem may be a yield damaging problem for the patterning system (e.g.,the lithographic projection apparatus 100) due to, for example, theshort working distance. Therefore, a solution of mitigating thecontamination problem during the patterning process is desirable.

It should be appreciated that in an embodiment, the projection systemmay be a part of the patterning device as described hereafter. As such,the optical lenses of the projection system may therefore be a part ofthe patterning device. However, in some other examples, the projectionsystem and the patterning device may be separate components of thepatterning system (e.g., the lithographic projection apparatus 100). Assuch, the optical lenses of the projection system may not be a part ofthe patterning device.

In an embodiment, a solution involves placing one or more fluid removalunits in proximity to the patterning device (e.g., the patterning device1700). The one or more fluid removal units may suck up the respectivenearby fluid (e.g., gas such as air), which causes a pressure drop nearthe one or more fluid removal units. Because of the pressure drop,surrounding fluid moves toward the proximity of the one or more fluidremoval units and is sucked up by the one or more fluid removal units.The surrounding fluid may flow toward the one or more fluid removalunits through the spaces between the adjacent MLA modules of thepatterning device and between the layer of photoresist and thepatterning device. The flowing fluid carries contamination (e.g., piecesof photoresist, outgassed material, etc.) away and toward the one ormore fluid removal units, and in an embodiment, into the one or morefluid removal units. As a result, this process may greatly reduce theeffects of contamination between the layer of photoresist and thepatterning device. As such, the contamination on the lenses of thepatterning device can be greatly reduced.

Various embodiments of placing the one or more fluid removal units inproximity to the patterning device are shown in FIGS. 18A and 18B, 19Aand 19B, and 20A and 20B depending on the number of fluid removal unitsand respective locations of the one or more fluid removal units withrespect to the patterning device. Although only three embodiments areshown, it should be understood that the number and/or locations of theone or more fluid removal units of the embodiments are non-limiting.

In an embodiment, a fluid removal unit 1820 is situated on top of (orbelow) the patterning device 1810. The patterning device 1810 may beconfigured similarly as the patterning device 1720. FIG. 18A depicts aschematic top view of the patterning device 1810 with the fluid removalunit 1820. As shown in this example, the patterning device 1810 includestwo rows of MLA modules 1815. The adjacent MLA modules 1815 in each roware separated by an open spacing 1830. The two rows of the MLA modules1815 are arranged in a way that patterns produced by the two rows of theMLA modules 1815 are interleaved, producing a continuous pattern on thesubstrate 1840. In an embodiment, an open spacing is provided betweenadjacent rows of MLA modules 1815, although there need not be one. Thecross-section of the fluid removal unit 1820 has a circular shape in theX-Y plane as shown in FIG. 18A. In some other examples, thecross-section of the fluid removal unit 1820 may have any other suitableshape. In an embodiment, the fluid removal unit 1820 covers at least onespacing area (e.g., the spacing 1830 and/or, if provided, the spacingbetween adjacent rows of MLA modules 1815) between the MLA modules 1815of the patterning device 1810.

FIG. 18B depicts a schematic side view (in the Y-direction with just onerow of MLA modules 1815 depicted for convenience) of the patterningdevice 1810 of FIG. 18A with the fluid removal unit 1820 on top of (orbelow) the patterning device 1810 according to an embodiment. As shownin this embodiment, the substrate 1840 is located below the patterningdevice 1810. A layer of photoresist 1835 is arranged on top of thesubstrate 1840. During the patterning process, there is a relativemovement between the patterning device 1810 and the substrate 1840 inthe scanning direction 1850. As such, each of the MLA modules 1815 maygenerate a pattern on a different portion of the photoresist layer 1835on the substrate 1840 (although there may be overlap between the areascovered by two or more of the MLA modules 1815). Therefore, the MLAmodules 1815 of the patterning device 1810 may collectively generatepatterns that cover the whole width 1845 of the substrate 1840 in theX-Z plane. The fluid removal unit 1820 on top of the patterning device1810 is configured to reduce or prevent contamination of the opticallenses of the MLA modules 1815. As shown, the cross-section of the fluidremoval unit 1820 in the X-Z plane has a triangular shape. However, itshould be appreciated that the cross-section of the fluid removal unit1820 in the X-Z plane may have any suitable shape. In an embodiment, thefluid removal unit 1820 need not span the width 1845 of the substrate1840.

In operation of the fluid removal unit 1820, the fluid removal unit 1820sucks up nearby fluid, causing a pressure drop near the fluid removalunit 1820. As such, fluid between the photoresist layer 1835 and thepatterning device 1810 is exhausted up (as shown by the arrows) throughthe spacing areas in the patterning device 1810 due to the pressure dropnear the fluid removal unit 1820. In an embodiment, the pressure drop isgreat enough to cause a horizontal flow between the MLA modules 1815 andthe substrate 1840. The exhausted fluid carries away contaminationbetween the layer of photoresist 1835 and the patterning device 1810. Inan embodiment, the contamination is sucked up by the fluid removal unit1820. As a result, the contamination on the lenses of the MLA modules1815 (e.g., due to outgassing) can be greatly reduced.

In an embodiment, a fluid removal unit 1920 is situated beside apatterning device 1910. FIG. 19A depicts a schematic top view of thepatterning device 1910 with the fluid removal unit 1920. As shown inthis example, the patterning device 1910 includes, as a non-limitingexample, two rows of MLA modules 1915 configured similarly as thepatterning device 1810. Additionally, the MLA modules 1915 are similarto the MLA modules 1815. The spacing 1930 between adjacent MLA modules1915 in each row of the patterning device 1910 and/or the spacingbetween adjacent rows of MLA modules 1915 can be similar to that of theMLA modules 1815 of patterning device 1810.

As shown in FIG. 19A, the fluid removal unit 1920 is situated at theback side of the patterning device 1910. In other examples, the fluidremoval unit 1920 may be situated at the front side of the patterningdevice 1910, at the left side of the patterning device 1910, at theright side of the patterning device 1910, and/or any other suitableplace near the patterning device 1910. More than one fluid removal unit1920 can be provided and can be located at different locations. See,e.g., FIGS. 20A and 20B. As shown, the cross-section of the fluidremoval unit 1920 has an elliptical shape in the X-Y plane. However, itshould be appreciated that the cross-section of the fluid removal unit1920 may have another suitable shape in the X-Y plane.

FIG. 19B depicts a schematic side view (in the Y-direction with just onerow of MLA modules 1915 depicted for convenience) of the patterningdevice 1910 of FIG. 18A with the fluid removal unit 1920 on a side ofthe patterning device 1910. As shown, a substrate 1940 is situated belowthe patterning device 1910. A layer of photoresist 1935 is arranged ontop of the substrate 1940. The substrate 1940 and the layer ofphotoresist 1935 are similar to the substrate 1840 and the layer ofphotoresist 1835, respectively. The fluid removal unit 1920 is similarto the fluid removal unit 1820. As shown, the cross-section of the fluidremoval unit 1920 in the X-Z plane has a triangular shape. However, itis appreciated that the cross-section of the fluid removal unit 1920 inthe X-Z plane may have any other suitable shape. During the patterningprocess, there is relative movement between the patterning device 1910and the substrate 1940 in the scanning direction 1950. As such, each ofthe MLA modules 1915 may generate a pattern on a different portion ofthe photoresist layer 1935 on the substrate 1940 (although there may beoverlap between the areas covered by two or more of the MLA modules1915). Therefore, the MLA modules 1915 of the patterning device 1910 maycollectively generate patterns that cover the whole width 1945 of thesubstrate 1940 in the X-Z plane.

In operation of the fluid removal unit 1920, the fluid removal unit 1920sucks up nearby fluid, causing a pressure drop near the fluid removalunit 1920. As such, the fluid above (or below) the patterning device1910 is drawn through (as shown by the arrows) the spacing areas in thepatterning device 1910 and then moves (as shown by the arrows) towardthe fluid removal unit 1920 due to the pressure drop near the fluidremoval unit 1920. In an embodiment, there is no open spacing betweenMLA modules 1915 and so the fluid is drawn across the substrate 1940from an opposite side of the substrate 1940. During the process, thefluid carries contamination between the layer of photoresist 1935 andthe patterning device 1910 away from the MLA modules 1915 and, in anembodiment, the contamination is sucked up by the fluid removal unit1920. As a result, contamination of the lenses of the MLA modules 1915can be greatly reduced.

In an embodiment, one or more fluid removal units 2020 are situated onopposite sides of the patterning device 2010. FIG. 20A depicts aschematic top view of a patterning device with a fluid removal unit onopposite sides (e.g., the front and back sides) of the patterning device2010. As shown in this example, the patterning device 2010 includes tworows of MLA modules 2015 configured similarly as the patterning devices1810, 1910. Additionally, the MLA modules 2015 are similar to the MLAmodules 1815, 1915. The spacing 2030 between adjacent MLA modules 2015in each row of the patterning device 2010 and/or between adjacent rowsof MLA modules 2015 can be similar to that of the MLA modules 1815, 1915of patterning device 1810, 1910. As shown, the cross-section of each ofthe fluid removal units 2020 has an elliptical shape in the X-Y plane.However, it should be appreciated that the cross-section of each of thefluid removal units 2020 may have other suitable shape in the X-Y plane.

FIG. 20B depicts a schematic side view (in the Y-direction with just onerow of MLA modules 2015 depicted for convenience) of the patterningdevice 2010 with the fluid removal unit 2020 on each side of thepatterning device 2010. As shown, a substrate 2040 is situated below thepatterning device 2010. A layer of photoresist 2035 is arranged on topof the substrate 2040. The substrate 2040 and the layer of photoresist2035 are similar to the substrate 1940 and the layer of photoresist1935, respectively. As shown, the cross-section of the fluid removalunit 2020 in the X-Z plane has a triangular shape. However, it isappreciated that the cross-section of the fluid removal unit 2020 in theX-Z plane may have any other suitable shape. During the patterningprocess, there is a relative movement between the patterning device 2010and the substrate 2040 in the scanning direction 2050. As such, each ofthe MLA modules 2015 may generate a pattern on a different portion ofthe photoresist layer 2035 on the substrate 2040 (although there may beoverlap between the areas covered by two or more of the MLA modules2015). Therefore, the MLA modules 2015 of the patterning device 2010 maycollectively generate patterns that cover the whole width 2045 of thesubstrate 2040 in the X-Z plane.

In operation of the fluid removal units 2020, each of the fluid removalunits 2020 sucks up nearby fluid, causing a pressure drop near each ofthe fluid removal units 2020. As such, the fluid above (or below) thepatterning device 2010 is drawn through the spacing areas (as shown bythe arrows) in the patterning device 2010 and then moves (as shown bythe arrows) toward the fluid removal units 2020 due to the pressure dropnear each of the fluid removal units 2020. In an embodiment, there is noopen spacing between MLA modules 2015 and so the fluid is drawn acrossthe substrate 2040 from an opposite side of the substrate 2040. Duringthe process, the fluid carries contamination between the layer ofphotoresist 2035 and the patterning device 2010 away from the MLAmodules 2015 and, in an embodiment, the contamination is sucked up bythe fluid removal units 2020. As a result, contamination of the lensesof the MLA modules 2015 can be greatly reduced.

Reducing the spot size of each individually addressable element of thepatterning device 104, 1560, 740, 940, and 1700, for example, to 1 μmmay provide very fine patterning resolution. However, on the other hand,the number of the individually addressable elements that are required inthe patterning device to cover a whole width of the substrate isincreased dramatically due to a smaller spot size. As such, the memorybandwidth and/or processing power to control such a large amount ofindividually addressable elements in the patterning device (e.g.,turning “ON” or “OFF” of each individual addressable element in thepatterning process) are increased significantly. For example, reducingthe spot size of each individually addressable element of the patterningdevice from 2 μm to 1 μm may improve the patterning resolution by afactor of two. However, the number of the individually addressableelements needed to cover the same width of the substrate is doubled.Accordingly, memory bandwidth and/or processing power for controllingthe individually addressable elements of the patterning device aredoubled as well. As a result, the cost of making and using thelithographic apparatus tool including the patterning device, forexample, in the manufacturing of the flat panel displays becomes muchmore expensive. Additionally, reducing the spot size of eachindividually addressable element of the patterning device, for example,from 2 μm to 1 μm may further quadruple the local current intensity ofeach individually addressable element, which in turn decreases thelifetime of each individually addressable element of the patterningdevice. Therefore, there is a need for a patterning system that iscapable of not only producing patterns with very fine resolution, butalso consumes much less memory bandwidth and/or processing power.

Not all patterns, or all parts of patterns, need to be produced usingindividually addressable elements with a fine radiation spot size (e.g.,1 μm). For example, a pattern with a width of 2 μm may be produced usingone individually addressable element with a radiation spot size of 2 μm,rather than using two individually addressable elements each with aradiation spot size of 1 μm. By using a larger spot size, the memorybandwidth and/or processing power to produce such pattern (i.e., a lowresolution pattern) may be cut in half.

So, in an embodiment, two or more different spot sizes are provided toselectively produce patterns or portions of patterns suited from thedifferent spot sizes. An individually addressable element with a fineradiation spot size (e.g., 1 μm) is referred to herein as a highresolution individually addressable element. In an embodiment, there maybe more than one type of high resolution individually addressableelement, i.e., two different fine spot sizes. An individuallyaddressable element with a coarse radiation spot size (e.g., 2 μm) isreferred to herein as a low resolution individually addressable element.In an embodiment, there may be more than one type of low resolutionindividually addressable element, i.e., two different coarse spot sizes.Accordingly, there are some patterns, or portions thereof, that can onlybe produced using the high resolution individually addressable elements,not the low resolution individually addressable elements. Such patterns,or portions thereof, are referred to as high resolution patterns.Accordingly, the patterns, or portions thereof, that can be produced bylow resolution individually addressable elements (or by both highresolution individually addressable elements and low resolutionindividually addressable elements) are referred to as low resolutionpatterns.

Thus, in an embodiment, by incorporating both high resolutionindividually addressable elements and low resolution individuallyaddressable elements in a patterning device, the patterning device mayproduce patterns on the substrate with reduced memory bandwidth and/orprocessing power, while maintaining the capability of producing highresolution patterns on the substrate. In addition, the consumption ofmemory bandwidth and/or processing power may be reduced or minimized bymaximizing the use of low resolution individually addressable elementsof the patterning device in the patterning process. Further, thereliability and/or lifetime of the patterning device may be improved byincreasing or maximizing the use of low resolution individuallyaddressable elements, which have a lower local current intensity. Itshould be appreciated that although the patterning device in theexamples described herein may include individually addressable elementshaving two different spot sizes, in some other examples, the patterningdevice may include individually addressable elements having three ormore different spot sizes.

Referring to FIG. 21, a schematic top view of a part of a lithographicapparatus according to an embodiment for exposing substrates in themanufacture of, for instance, flat panel displays (e.g., LCDs, OLEDdisplays, etc.) is depicted. Like the lithographic apparatus 100 shownin FIG. 2, the lithographic apparatus 100 comprises a substrate table2106 to hold a flat panel display substrate 2114, a positioning device2116 to move the substrate table 2106 in up to 6 degrees of freedom, anda patterning device 2104.

The patterning device 2104 comprises a sensor system 2150 comprising analignment sensor to determine alignment between the individuallyaddressable elements 2135, 2145 and the substrate 2114 and/or a levelsensor to determine whether the substrate 2114 is level with respect tothe projection of the pattern by the individually addressable elements2135, 2145.

The patterning device 2104 comprises a plurality of high resolutionindividually addressable elements 2135 arranged on a frame 2160. Thedepiction of the elements 2135 in FIG. 21 is highly schematic and may bearranged more like shown in FIGS. 4-9. As described above, the radiationspot size produced from each of the high resolution individuallyaddressable elements 2135 may be 1 μm. In this embodiment, each of thehigh resolution individually addressable elements 2135 is a radiationemitting diode, e.g., an LED. In an embodiment, each of the highresolution individually addressable elements 2135 is a laser diode. Inan embodiment, each of the high resolution individually addressableelements 2135 is a vertical external cavity surface emitting lasers(VECSEL) or a vertical cavity surface emitting lasers (VCSEL). For thesake of simplicity, three rows of the high resolution individuallyaddressable elements 2135 extending along the Y-direction are shown inFIG. 21 and having sufficient columns to cover the whole width of thesubstrate; a greater number of rows of high resolution individuallyaddressable elements 2135 may be arranged on the frame 2160. In anembodiment, each of the high resolution individually addressableelements 2135 is configured to provide a plurality of radiation beamsfor producing at least a high resolution pattern on the substrate 2135.In an embodiment, each of the high resolution individually addressableelements 2135 depicted in FIG. 21 comprises a plurality of highresolution individually addressable elements 2135 (thus each circlelabeled 2135 in FIG. 21 represents a plurality of individuallyaddressable elements 2135). Further, in an embodiment, a number of therows of high resolution individually addressable elements 2135 arestaggered in the Y-direction from one or more adjacent rows ofindividually addressable elements 2135 as shown in FIG. 21. In anembodiment, the high resolution individually addressable elements 2135are substantially stationary, i.e., they do not move significantlyduring projection.

The patterning device 2104 further comprises a plurality of lowresolution individually addressable elements 2145 arranged on the frame2160. The depiction of the elements 2145 in FIG. 21 is highly schematicand may be arranged more like shown in FIGS. 4-9. The low resolutionindividually addressable elements 2145 are configured similarly as thehigh resolution individually addressable elements 2135 as describedabove except that the radiation spot sizes of the low resolutionindividually addressable elements 2145 are larger than the radiationspot sizes of the high resolution individually addressable elements2135. As described above, the radiation spot size produced from each ofthe low resolution individually addressable elements 2145 may be 2 μm.For the sake of simplicity, two rows of the low resolution individuallyaddressable elements 2145 extending along the Y-direction are shown inFIG. 21; a greater number of rows of low resolution individuallyaddressable elements 2145 may be arranged on the frame 2160. In anembodiment, the number of the low resolution individually addressableelements 2145 may be large enough to cover the whole width of thesubstrate 2114. However, this is not required if the high resolutionindividually addressable elements 2135 reach the remaining portion ofthe width. In an embodiment, each of the low resolution individuallyaddressable elements 2145 is configured to provide a plurality ofradiation beams for producing a low resolution pattern on the substrate2135. In an embodiment, each of the low resolution individuallyaddressable elements 2145 depicted in FIG. 21 comprises a plurality oflow resolution individually addressable elements 2145 (thus each circlelabeled 2145 in FIG. 21 represents a plurality of low resolutionindividually addressable elements 2145). Further, in an embodiment, anumber of the rows of low resolution individually addressable elements2145 are staggered in the Y-direction from one or more adjacent rows oflow resolution individually addressable elements 2145 as shown in FIG.21. In an embodiment, the low resolution individually addressableelements 2145 are substantially stationary, i.e., they do not movesignificantly during projection.

As shown in FIG. 21, the plurality of high resolution individuallyaddressable elements 2135 and the plurality of low resolutionindividually addressable elements 2145 are arranged separately on theframe 2160 of the patterning device. In an embodiment, the plurality ofhigh resolution individually addressable elements 2135 and the pluralityof low resolution individually addressable elements 2145 may be mixedwith each other. For example, the rows of high resolution individuallyaddressable elements 2135 may be interleaved completely or partiallywith the rows of low resolution individually addressable elements 2145.In an embodiment, the high resolution individually addressable elements2135 and low resolution individually addressable elements 2145 can beintermixed in, e.g., a checkerboard fashion.

In an embodiment, the plurality of high resolution individuallyaddressable elements 2135 are situated on a first insertion structureinstalled on frame 2160 of the patterning device 2104. Additionally, theplurality of low resolution individually addressable elements 2145 aresituated on a second insertion structure installed on frame 2160 of thepatterning device. The first insertion structure and/or the secondinsertion structure may be readily taken off the frame 2160 of thepatterning device 2104 for, e.g., repair or replacement of one or more,if any, broken individually addressable elements. In some examples, thefirst insertion structure and/or second insertion structure may bereplaced with a new one including a plurality of individuallyaddressable elements having a different radiation spot size, e.g., fortool update in manufacture of a different product. In an embodiment, thetool may include a plurality of low or high resolution individuallyaddressable elements 2135, 2145 (either on an insertion structure ornot) and the tool may be then upgraded by providing an insertionstructure having the other of the high or low individually addressableelements 2135, 2145.

In operation of the lithographic apparatus 100, a panel displaysubstrate 2114 is loaded onto the substrate table 2106 using, forexample, a robot handler (not shown). The substrate 2114 is thendisplaced in the X-direction as shown by arrow 2123 under the frame2160. The substrate 2114 is measured by the level sensor and/oralignment sensor 2150 and then is exposed to high resolution patternsusing one or more of the plurality of high resolution individuallyaddressable elements 2135 and/or low resolution patterns using one ormore of the plurality of low resolution individually addressableelements 2145. One or more lenses may be used to project the patterningbeams from the high resolution individually addressable elements 2135and/or the low resolution individually addressable elements 2145 to thesubstrate 2114. The high resolution individually addressable elements2135 and/or the low resolution individually addressable elements 2145may be operated, for example, to provide pixel-grid imaging as discussedherein.

As shown, the patterning device 2104 comprises a plurality ofindividually addressable elements 2135, 2145 having two different spotsizes, which provides two patterning resolutions accordingly. In anembodiment, the patterning device 2104 may comprise a plurality ofindividually addressable elements having three or more different spotsizes. The patterning device 2104 may employ the individuallyaddressable elements to provide three or more different patterningresolutions, for example, in the manufacture of flat panel displays.

FIG. 22 depicts an example of decomposing a pattern to a high resolutionpattern and a low resolution pattern. As shown in FIG. 22, the wholepattern 2200 is decomposed to a high resolution pattern (i.e., the darkarea in FIG. 22) and a low resolution pattern (i.e., the light area inFIG. 22). The high resolution pattern is to be produced by the highresolution individually addressable elements (e.g., the high resolutionindividually addressable elements 2135), and the low resolution patternis to be produced by the low resolution individually addressableelements (e.g., the low resolution individually addressable elements2145).

As can be seen, the pattern 2200 may be decomposed to a different highresolution pattern and a different low resolution pattern in variouscombinations based on the spot size ratio between the low resolutionindividually addressable elements (e.g., the low resolution individuallyaddressable elements 2145) and the high resolution individuallyaddressable elements (e.g., the high resolution individually addressableelements 2135). The best benefit (e.g., minimal memory bandwidth and/orprocessing power for producing a pattern, e.g., the pattern 2200) may beobtained when the use of low resolution individually addressableelements 2145 is maximized. This can be done by decomposing the patternin a manner that results in a maximal low resolution pattern to beproduced by the low resolution individually addressable elements giventhe spot size ratio between the low resolution individually addressableelements and the high resolution individually addressable elements.

So, the selection of the spot size ratio between the low resolutionindividually addressable elements and the high resolution individuallyaddressable elements may determine the best benefit (e.g., minimalmemory bandwidth and/or processing power for producing patterns on thesubstrate) that may be obtained. For example, when the spot size of thelow resolution individually addressable elements is similar to the spotsize of the high resolution individually addressable elements (i.e., thespot size ratio between the low resolution individually addressableelements and the high resolution individually addressable elements isclose to 1), the patterning device 2104 functions similar to thepatterning device 104. As such, the requirement of memory bandwidthand/or processing power to produce the pattern is still high. As anotherexample, when the spot size of the low resolution individuallyaddressable elements is much larger than the spot size of the highresolution individually addressable elements (i.e., the spot size ratiobetween the low resolution individually addressable elements and thehigh resolution individually addressable elements is very large, forexample, 1000), there might be no way to decompose the pattern to a lowresolution pattern that can be produced by the low resolutionindividually addressable elements. As a result, the whole pattern has tobe produced using the high resolution individually addressable elements.As such, the memory bandwidth and/or processing power to produce thepattern is still high. In either example, there is no benefit byincluding both the low resolution individually addressable elements andthe high resolution individually addressable elements in the patterningdevice given an inappropriate spot size ratio. Thus, it would bedesirable to arrive at an appropriate spot size ratio.

Data rate is a key performance indicator (KPI) of memory bandwidth andprocessing power. Specifically, a high data rate is indicative ofrelatively large memory bandwidth and/or high processing power.Accordingly, a low data rate is indicative of relatively low memorybandwidth and/or low processing power. Due to the spot size differencebetween the high resolution individually addressable elements and thelow resolution individually addressable elements, the relationshipbetween the data rates of the high resolution individually addressableelements and the low resolution individually addressable elements may beexpressed by:

$\begin{matrix}{{DR}_{low} = \frac{{DR}_{high}}{r^{2}}} & (1)\end{matrix}$where DR_(low) is the data rate of a low resolution individuallyaddressable element, DR_(high) is the data rate of a high resolutionindividually addressable element, and r (r>1) is a spot size ratiobetween the low resolution individually addressable element and the highresolution individually addressable element.

For simplicity, assuming the data rate of the high resolutionindividually addressable element, DR_(high) is 100, equation (1)becomes:

$\begin{matrix}{{DR}_{low} = \frac{100}{r^{2}}} & (2)\end{matrix}$

Table 1 shows a plurality of example data rates of the low resolutionindividually addressable element, DR_(low) corresponding to differentspot size ratio, r based on equation (2).

TABLE 1 Data rate scaling as function of spot size ratio r DR_(high) 100100 100 100 100 100 DR_(low) 1 4 16 25 44.4 100 r 10 5 2.5 2 1.5 1

As described above, a pattern to be produced on the substrate may bedecomposed to a high resolution pattern and a low resolution pattern.The high resolution pattern is to be produced by high resolutionindividually addressable elements. The low resolution pattern is to beproduced by low resolution individually addressable elements. Therefore,the resulting data rate, DR, to produce the whole pattern may beexpressed by:DR=xDR_(high)+(1−x)DR_(low)  (3)where x is the fraction of the high resolution pattern in the wholepattern. Thus, x is the fraction of the pattern which can only beproduced using the high resolution individually addressable elements,not the low resolution individually addressable elements. For example,if 20% of the whole pattern is decomposed to the high resolutionpattern, then the value of x is 0.2. Thus, a larger x is indicative of amore complex pattern and a smaller x is indicative of a simpler pattern.As such, x may be referred to as pattern complexity.

By assuming DR_(high) is 100 and incorporating equation (2) to equation(3), equation (3) becomes:

$\begin{matrix}{{DR} = {{\left( {1 - \frac{1}{r^{2}}} \right)100x} + \frac{100}{r^{2}}}} & (4)\end{matrix}$

As can be seen from equation (4), the minimal data rate DR is obtainedwhen x is minimized given the spot size ratio r. This indicates that thebest benefit can be obtained when the use of the high resolutionindividually addressable elements in producing the pattern on thesubstrate is minimized and the use of the low resolution individuallyaddressable elements in producing the pattern on the substrate ismaximized given the spot size ratio r.

FIG. 23 is a graph of data rate DR on the vertical axis versus patterncomplexity x (shown as a percentage) on the horizontal axis, accordingto equation (4) assuming DR_(high) is 100. The lines 2210-2260correspond to the spot size ratio of 10, 5, 2.5, 2, 1.5, and 1,respectively. As shown, when the pattern complexity is 100 meaning thewhole pattern has to be produced using the high resolution individuallyaddressable elements, the highest data rate is required to produce thepattern regardless of the spot size ratio r. Otherwise, decreasing thespot size ratio, r, would increase the minimal data rate that isrequired to produce the pattern. Given a spot size ratio (i.e., in eachline 2210-2260), increasing the pattern complexity may result in anincrease of the data rate that is required to produce the pattern. In anembodiment, a spot size ratio r may be selected between 1.2 and 5,desirably between 1.5 and 2.5.

FIGS. 24A-D depict various examples of producing a pattern using highresolution individually addressable elements and low resolutionindividually addressable elements with different spot size ratios. Asshown, the pattern 2400 has a width 2410 of, e.g., 6 μm and a height2420 of, e.g., 4.5 μm. The patterning complexity x with respect to thepattern 2400 is closely correlated with the spot size ratio, r, betweenthe low resolution individually addressable elements 2430 and the highresolution individually addressable elements 2440. A minimal data raterequired to produce the pattern 2400 may vary by varying the spot sizeratio.

In FIG. 24A, the spot size ratio between the low resolution individuallyaddressable element 2430 and the high resolution individuallyaddressable element 2440 is 1.25. To minimize the use of the highresolution individually addressable element in producing the pattern2400, the pattern 2400 is decomposed to a low resolution pattern (asshown in the solid area) and a high resolution pattern (as shown in thelight area). The low resolution pattern is to be produced using four lowresolution individually addressable elements 2430. The high resolutionpattern is to be produced using one high resolution individuallyaddressable element 2440. As such, the pattern complexity x isdetermined to be about 0.17, meaning about 17% of the pattern 2400 isthe high resolution pattern and about 83% of the pattern 2400 is the lowresolution pattern. According to equation (4), the minimal data rate iscalculated to be about 70 (assuming DR_(high) is 100).

In FIG. 24B, for the same pattern 2400 as in FIG. 24A, the spot sizeratio between the low resolution individually addressable element 2430and the high resolution individually addressable element 2440 is 2. Thewhole pattern 2400 may be produced using only the three low resolutionindividually addressable elements 2430. As such, the pattern complexityx is determined to be 0. According to equation (4), the minimal datarate is calculated to be 25 (assuming DR_(high) is 100).

In FIG. 24C, for the same pattern 2400 as in FIG. 24A, the spot sizeratio between the low resolution individually addressable element 2430and the high resolution individually addressable element 2440 is 2.5. Tominimize the use of the high resolution individually addressableelements 2440 in producing the pattern 2400, the pattern 2400 isdecomposed to a low resolution pattern (as shown in the solid area) anda high resolution pattern (as shown in the light area). The lowresolution pattern is to be produced using two low resolutionindividually addressable elements 2430. The high resolution pattern isto be produced using one high resolution individually addressableelement 2440. As such, the pattern complexity x is determined to beabout 0.17, meaning about 17% of the pattern 2400 is the high resolutionpattern and about 83% of the pattern 2400 is the low resolution pattern.According to equation (4), the minimal data rate is calculated to be 30(assuming DR_(high) is 100).

In FIG. 24D, for the same pattern 2400 as in FIG. 24A, the spot sizeratio between the low resolution individually addressable element 2430and the high resolution individually addressable element 2440 is 4. Tominimize the use of the high resolution individually addressable elementin producing the pattern 2400, the pattern 2400 is decomposed to a lowresolution pattern (as shown in the solid area) and a high resolutionpattern (as shown in the light area). The low resolution pattern is tobe produced using one low resolution individually addressable elements2430. The high resolution pattern is to be produced using two highresolution individually addressable elements 2440. As such, the patterncomplexity x is determined to be about 0.33, meaning about 33% of thepattern 2400 is the high resolution pattern and about 67% of the pattern2400 is the low resolution pattern. According to equation (4), theminimal data rate is calculated to be 37.5 (assuming DR_(high) is 100).

Referring to FIG. 25, a flow diagram illustrating an example patterningprocess is depicted according to an embodiment. In an embodiment, thedata flow starts from various inputs and processes them, e.g., in realtime, to generate data for addressing the individually addressableelements. In an embodiment, before exposure starts, the individual spotsof the individually addressable elements are calibrated in terms of,e.g., emission power and/or profile, and in position. These aretranslated into calibration parameters and data for each spot that fullydescribes its effect on the overall exposure. The use of thiscalibration information is described further hereafter. Further, thedata flow starts with a nominal pattern to be exposed onto thesubstrate. The nominal pattern could be the entire digitized file forthe whole substrate, or a portion of this file for the current exposurearea as well as a predefined part of the subsequent area to dopre-calculation and fill the write buffers. Further, during exposure,metrology may be performed on the substrate to determine the actualposition of features, so that on-the-fly correction can be done tomodify the exposure pattern in case of e.g. local deformation or shift.These measurements are translated into transform parameters (asdiscussed further hereafter) to locally modify the nominal pattern tomatch the pattern on the substrate. As noted above, in an embodiment,these inputs are processed in real-time (desirably using a buffer),resulting in output to the individually addressable elements,synchronized with the substrate movement.

A nominal pattern 2510 to be produced on a substrate is decomposed to ahigh resolution pattern 2540 and a low resolution pattern 2550 in apattern decomposition procedure 2530 based on the spot size ratio 2520between the low resolution individually addressable elements and thehigh resolution individually addressable elements. As described above,the high resolution pattern 2540 is to be produced by the highresolution individually addressable elements, and the low resolutionpattern 2550 is to be produced by the low resolution individuallyaddressable elements. Then, in an embodiment, two separate paths aretaken, e.g., in parallel, for generating a control file for each of thehigh resolution individually addressable elements and the low resolutionindividually addressable elements to produce the high resolution pattern2540 and the low resolution pattern 2550, respectively.

In a first path, a first control file for the high resolutionindividually addressable elements is created in procedure 2570 based onthe high resolution pattern 2540, based on a plurality of spotparameters 2560 associated with the high resolution individuallyaddressable elements, and based on a plurality of transform parameters2565. The plurality of spot parameters 2560 may be determined during acalibration of the high resolution individually addressable elementsbefore the patterning process. The plurality of spot parameters 2560 mayinclude, but is not limited to, the radiation intensity, the radiationspot size, the radiation beam shape, calibration data, and/or a grayscale factor of each high resolution individually addressable element(including, optionally, a measure of variance of the parameters overtime). The plurality of transform parameters 2565 may be determinedbased on the actual positions of the physical structures produced on thesubstrate, which may be measured in real time by a local metrology unitduring the patterning process. The plurality of transform parameters2565 may be used to modify the high resolution pattern to be produced bythe high resolution individually addressable elements in case thereal-time measurement indicates the physical structures produced on thesubstrate are deformed, translated, shifted, rotated, or any combinationthereof. Then, in procedure 2575, the first control file may betransmitted to and stored in one or more buffers or memory units (e.g.,the local memories 1430) associated with the plurality of highresolution individually addressable elements. In the patterning processof the high resolution patterns, one or more control circuits (e.g., thelocal processing units 1450) may operate each of the plurality of highresolution individually addressable elements according to the controlfile 2570. In an embodiment, a control signal for each of the pluralityof high resolution individually addressable element is generated basedon the first control file, for example, to turn “ON” or “OFF” each ofthe high resolution individually addressable element in production ofthe high resolution patterns.

In a second path, a second control file for the low resolutionindividually addressable elements is created in procedure 2585 based onthe low resolution pattern 2550, based on a plurality of spot parameters2580 associated with the low resolution individually addressableelements, and based on the plurality of transform parameters 2565. Theplurality of spot parameters 2580 may be determined during a calibrationof the low resolution individually addressable elements before thepatterning process. The plurality of spot parameters 2580 may include,but is not limited to, the radiation intensity, the radiation spot size,the radiation beam shape, calibration data, and/or a gray scale factorof each low resolution individually addressable element (including,optionally, a measure of variance of the parameters over time). Theplurality of transform parameters 2565 may be used to modify the lowresolution pattern 2550 to be produced by the low resolutionindividually addressable elements in case the real-time measurementindicates the physical structures produced on the substrate aredeformed, translated, shifted, rotated, or any combination thereof. Inan embodiment, the transform parameters are the same as those for thehigh resolution individually addressable elements except used with atime delay if the low and high resolution individually addressableelements are separated (e.g., one is behind the other). In anembodiment, the low and high resolution individually addressableelements have their own transform parameters measured by, e.g., adedicated metrology arrangement. Then, in procedure 2590, the secondcontrol file may be transmitted to and stored in one or more buffers ormemory units (e.g., the local memories 1430) associated with theplurality of low resolution individually addressable elements. In thepatterning process of the low resolution patterns, one or more controlcircuits (e.g., the local processing units 1450) may operate each of theplurality of low resolution individually addressable elements accordingto the control file 2585. In an embodiment, a control signal for each ofthe plurality of low resolution individually addressable element isgenerated based on the second control file, for example, to turn “ON” or“OFF” each of the low resolution individually addressable element inproduction of the low resolution patterns.

As described above, the patterning device 2104 may include a pluralityof individually addressable elements having three or more spot sizes. Inan embodiment, the nominal pattern 2510 may be decomposed into three ormore sub patterns in the procedure 2530 based on the spot size ratiosbetween the three or more spot sizes. Each of the three or more subpatterns is to be produced by a portion of the plurality of individuallyaddressable elements having one of the three or more spot sizes.Accordingly, a control file is created corresponding to each spot sizein a procedure similar to the procedure 2570 and 2585, and is finallytransmitted to and stored in one or more buffers associated with theindividually addressable elements having the respective spot size in aprocedure similar to the procedures 2575 and 2590.

It should be appreciated that the patterning process described in FIGS.21-25 is distinctive from electron-beam (e-beam) lithography technology,in which a plurality of electron beams are deflected and scanned overthe surface of the substrate to produce desired patterns on thesubstrate. In e-beam system, the radiation spot size and/or radiationdirection of each electron beam may be controlled by means of anelectro-magnetic field surrounding a stream of the electrons, e.g.,using one or more electro-magnetic lenses inside the e-beam tool. Thus,a movement of the substrate during projection of the e-beam radiation isnot used or necessary. In addition, the time for patterning thesubstrate in the e-beam system may be shortened by employing moreelectron beams in its process. On the contrary, in an embodiment, theradiation direction and spot size of each individually addressableelement of the patterning device 2104 as described herein is notadjustable like in an e-beam system. In addition, in an embodiment, thesubstrate is moved relative to the patterning device 2104. Further, thetime for patterning the substrate using patterning device 2014 dependson the velocity of the substrate. Given the velocity, increasing thenumber of individually addressable elements in the patterning device2014 does not change the time for patterning the substrate. Further,emitted power is used more effectively by using large, more robust andefficient individually addressable elements whenever possible, and onlyusing the small, less robust individually addressable elements whererequired to reach the desired resolution, which is also distinct from,e.g., the e-beam process where the different spot sizes are producedfrom a common electron beam system or identical electron beam systems.

In an embodiment, there is provided an exposure apparatus comprising: asubstrate holder constructed to support a substrate; a patterning deviceconfigured to provide radiation modulated according to a desiredpattern, the patterning device comprising a plurality of two-dimensionalarrays of radiation sources, each radiation source configured to emit aradiation beam; a projection system configured to project the modulatedradiation onto the substrate, the projection system comprising aplurality of optical elements arranged side by side and arranged suchthat a two-dimensional array of radiation beams from a two-dimensionalarray of radiation sources impinges a single optical element of theplurality of optical elements; and an actuator configured to providerelative motion between the substrate and the plurality oftwo-dimensional arrays of radiation sources in a scanning direction toexpose the substrate.

In an embodiment, the plurality of two-dimensional arrays of radiationsources sufficiently extend across the width of the substrate such thata scanning motion can expose substantially the entire width of thesubstrate to the plurality of beams at a same time. In an embodiment, afirst two-dimensional array of radiation sources is spatially separatedfrom a second two-dimensional array of radiation sources along thescanning direction such that at least some of the beams of the firsttwo-dimensional array would expose regions of the substrate thatinterleave regions of the substrate that would be exposed by at leastsome of the beams of the second two-dimensional array. In an embodiment,at least some of the two-dimensional arrays of beams have a squareshape. In an embodiment, at least one of the two-dimensional arrays ofbeams is configured such that the beams in the two-dimensional arrayhave essentially equal distances with neighboring beams. In anembodiment, a cross-sectional dimension of at least one of thetwo-dimensional arrays of radiation sources is less than or equal to thecross-sectional dimension of at least one of the optical elements. In anembodiment, at least one of the two-dimensional arrays of radiationsources comprises a bonding pad area around the array, the bonding padarea comprising a plurality of bond pads connected by respective linesto the radiation sources of the array. In an embodiment, the pluralityof radiation sources comprises light-emitting diodes (LEDs). In anembodiment, the plurality of radiation sources comprises verticalexternal cavity surface emitting lasers (VECSELs) or vertical cavitysurface emitting lasers (VCSELs). In an embodiment, the optical elementsare microlenses and the plurality of optical elements form atwo-dimensional microlens array. In an embodiment, the substrate is aradiation-sensitive substrate. In an embodiment, the substrate ismovable in the scanning direction and the plurality of two-dimensionalarrays of radiation sources is kept substantially stationary during ascanning motion to expose the substrate.

In an embodiment, there is provided a device manufacturing methodcomprising: providing a plurality of beams of radiation modulatedaccording to a desired pattern using a plurality of two-dimensionalarrays of radiation sources, each radiation source configured to emit aradiation beam; projecting the plurality of beams onto a substrate usinga plurality of optical elements arranged side by side, the opticalelements arranged such that a two-dimensional array of radiation beamsfrom a two-dimensional array of radiation sources impinges a singleoptical element of the plurality of optical elements; and providingrelative motion between the substrate and the plurality oftwo-dimensional arrays of radiation sources, in a scanning direction toexpose the substrate.

In an embodiment, the plurality of two-dimensional arrays of radiationsources sufficiently extend across the width of the substrate such thata scanning motion can expose substantially the entire width of thesubstrate to the plurality of beams at a same time. In an embodiment, afirst two-dimensional array of radiation sources is spatially separatedfrom a second two-dimensional array of radiation sources along thescanning direction such that at least some of the beams of the firsttwo-dimensional array would expose regions of the substrate thatinterleave regions of the substrate that would be exposed by at leastsome of the beams of the second two-dimensional array. In an embodiment,at least some of the two-dimensional arrays of beams have a squareshape. In an embodiment, at least one of the two-dimensional arrays ofbeams is configured such that the beams in the two-dimensional arrayhave essentially equal distances with neighboring beams. In anembodiment, a cross-sectional dimension of at least one of thetwo-dimensional arrays of radiation sources is less than or equal to thecross-sectional dimension of at least one of the optical elements. In anembodiment, at least one of the two-dimensional arrays of radiationsources comprises a bonding pad area around the array, the bonding padarea comprising a plurality of bond pads connected by respective linesto the radiation sources of the array. In an embodiment, the pluralityof radiation sources comprises light-emitting diodes (LEDs). In anembodiment, the plurality of radiation sources comprises verticalexternal cavity surface emitting lasers (VECSELs) or vertical cavitysurface emitting lasers (VCSELs). In an embodiment, the optical elementsare microlenses and the plurality of optical elements form atwo-dimensional microlens array. In an embodiment, the substrate is aradiation-sensitive substrate. In an embodiment, the method comprisesmoving the substrate in the scanning direction while the plurality oftwo-dimensional arrays of radiation sources are kept substantiallystationary during a scanning motion to expose the substrate.

In an embodiment, there is provided an exposure apparatus comprising: aplurality of arrays, each array having a plurality of radiation emittersand the radiation emitters configured to provide a plurality of beamsmodulated according to a desired pattern toward a substrate; an actuatorconfigured to adjust a position of the plurality of arrays as a unit;and a plurality of optical elements, each optical element configured toreceive beams emitted by one of the plurality of the arrays and projectthe beams onto the substrate.

In an embodiment, the actuator is configured to adjust a distancebetween the plurality of arrays and the substrate and/or adjust theangular orientation of the plurality of arrays relative to thesubstrate. In an embodiment, the actuator is configured to adjustpositional alignment of the plurality of arrays relative to anotherplurality of arrays. In an embodiment, the actuator comprises aplurality of actuators, at least one of the actuators situated at acorner of the plurality of arrays and/or the center of the plurality ofarrays. In an embodiment, the plurality of radiation emitters comprisesa plurality of radiation sources, each radiation source configured togenerate and emit electromagnetic radiation. In an embodiment, theplurality of radiation sources comprises light-emitting diodes (LEDs).In an embodiment, the plurality of radiation sources comprises verticalexternal cavity surface emitting lasers (VECSELs) or vertical cavitysurface emitting lasers (VCSELs). In an embodiment, a plurality ofoptical elements is attached to the plurality of arrays. In anembodiment, the plurality of radiation emitters of at least one of theplurality of arrays is arranged in a two-dimensional array. In anembodiment, the plurality of arrays is arranged in a two-dimensionalarray. In an embodiment, the plurality of arrays, the actuator and theplurality of optical elements form a module and further comprising aplurality of such modules arranged in an array. In an embodiment, theoptical elements are microlenses and the plurality of optical elementsform a microlens array. In an embodiment, the substrate is aradiation-sensitive substrate.

In an embodiment, there is provided a device manufacturing methodcomprising: adjusting a position of a plurality of arrays as a unitusing an actuator, each array having a plurality of radiation emitters,the radiation emitters configured provide a plurality of beams ofradiation; providing the plurality of beams of radiation from theplurality of emitters modulated according to a desired pattern; andprojecting the plurality of beams to a substrate by a plurality ofoptical elements, each optical element configured to receive beamsemitted by one of the plurality of the arrays.

In an embodiment, the adjusting comprises adjusting a distance betweenthe plurality of arrays and the substrate and/or adjusting the angularorientation of the plurality of arrays relative to the substrate. In anembodiment, the adjusting comprises adjusting positional alignment ofthe plurality of arrays relative to another plurality of arrays. In anembodiment, the actuator comprises a plurality of actuators, at leastone of the actuators situated at a corner of the plurality of arraysand/or the center of the plurality of arrays. In an embodiment, theplurality of radiation emitters comprises a plurality of radiationsources, each radiation source configured to generate and emitelectromagnetic radiation. In an embodiment, the plurality of radiationsources comprises light-emitting diodes (LEDs). In an embodiment, theplurality of radiation sources comprises vertical external cavitysurface emitting lasers (VECSELs) or vertical cavity surface emittinglasers (VCSELs). In an embodiment, a plurality of optical elements isattached to the plurality of arrays. In an embodiment, the plurality ofradiation emitters of at least one of the plurality of arrays isarranged in a two-dimensional array. In an embodiment, the plurality ofarrays is arranged in a two-dimensional array. In an embodiment, theplurality of arrays, the actuator and the plurality of optical elementsform a module and further comprising a plurality of such modulesarranged in an array. In an embodiment, the optical elements aremicrolenses and the plurality of optical elements form a microlensarray. In an embodiment, the substrate is a radiation-sensitivesubstrate.

In an embodiment, there is provided a device manufacturing methodcomprising: generating particles in a patterning apparatus; depositingthe particles onto a substrate in the patterning apparatus to form alayer of particles on the substrate; and applying a pattern in thepatterning apparatus to the deposited layer of particles.

In an embodiment, applying the pattern comprises projecting a beam ofradiation onto the substrate to at least partially sinter at least partof the particles on the substrate. In an embodiment, the method furthercomprises moving the substrate and wherein projecting the beam ofradiation comprises a projecting a plurality of modulated beams to themoving substrate in a pixel-grid imaging fashion. In an embodiment, thewidth of a majority of the particles is less or equal to 15 nanometers.In an embodiment, applying the pattern comprises producing a pattern inthe layer by at least partially sintering at least part of the particlesin the layer at a temperature of less than or equal to 200° C. In anembodiment, generating the particles comprises forming the particles bygenerating a spark between an anode and a cathode, wherein the particlesare formed from material of the anode, the cathode, or both. In anembodiment, the material comprises one or more selected from: aluminum,chromium, molybdenum, copper, gold, silver, titanium, and/or platinum.In an embodiment, forming the particles comprises forming the particlesin a substantially oxygen-free environment. In an embodiment, thesubstantially oxygen-free environment is a vacuum or is filled with agas comprising one or more selected from: nitrogen, helium, neon, argon,krypton, xenon, and/or radon. In an embodiment, the method furthercomprises entraining the particles in a stream of gas to agglomerateparticles and providing a further stream of gas downstream of the sparkto prevent or limit further agglomeration of particles. In anembodiment, the method further comprises moving the substrate andwherein depositing the particles comprises depositing the particles,during the movement of the substrate, to extend across the width of thesubstrate. In an embodiment, depositing the particles comprisescontrolling a travel direction of the particles by an electro-magneticfield around a stream of the particles. In an embodiment, depositing theparticles comprises carrying the particles in a stream of gas onto thesubstrate. In an embodiment, the substrate is a semiconductor-typesubstrate.

In an embodiment, there is provided a patterning apparatus, comprising:a substrate holder constructed to support a substrate; a particlegenerator configured to generate particles in the patterning apparatus,the particle generator configured to deposit the particles onto thesubstrate to form a layer of particles on the substrate; and a patterngenerator in the patterning apparatus, the pattern generator configuredto applying a pattern in the patterning apparatus to the deposited layerof particles.

In an embodiment, the pattern generator is configured to project a beamof radiation onto the substrate to at least partially sinter at leastpart of the particles on the substrate. In an embodiment, the apparatusfurther comprises an actuator to move the substrate and wherein thepattern generator is configured to project a plurality of modulatedbeams to the moving substrate in a pixel-grid imaging fashion. In anembodiment, the particle generator is configured to generate particlessuch that a width of a majority of the particles is less or equal to 15nanometers. In an embodiment, the pattern generator is configured toproduce a pattern in the layer by at least partially sintering at leastpart of the particles in the layer at a temperature of less than orequal to 200° C. In an embodiment, the particle generator comprises aspark discharge generator comprising an anode and a cathode andconfigured to generate a spark between the anode and the cathode,wherein the particles are formed from material of the anode, thecathode, or both. In an embodiment, the material comprises one or moreselected from: aluminum, chromium, molybdenum, copper, gold, silver,titanium, and/or platinum. In an embodiment, the particle generator isconfigured to form the particles in a substantially oxygen-freeenvironment. In an embodiment, the substantially oxygen-free environmentis a vacuum or is filled with a gas comprising one or more selectedfrom: nitrogen, helium, neon, argon, krypton, xenon, and/or radon. In anembodiment, the particle generator is configured to entrain theparticles in a stream of gas to agglomerate particles and furthercomprises an outlet to provide a further stream of gas downstream of thespark to prevent or limit further agglomeration of particles. In anembodiment, the apparatus further comprises an actuator configured tomove the substrate and a control system configured to control depositionof the particles such that, during the movement of the substrate, theparticles are provided to extend across the width of the substrate. Inan embodiment, the particle generator is configured to control a traveldirection of the particles by an electro-magnetic field around a streamof the particles. In an embodiment, the particle generator is configuredto provide the particles in a stream of gas onto the substrate. In anembodiment, the apparatus further comprises a control system configuredto control the thickness of a layer of the particles on the substrate.In an embodiment, the substrate is a semiconductor-type substrate.

In an embodiment, there is provided a device manufacturing methodcomprising: providing a plurality of beams of radiation modulatedaccording to at least two sub patterns of a pattern using a plurality ofradiation sources, the plurality of radiation sources producingradiation beams of at least two spot sizes such that each of theradiation beams having a same spot size of the at least two spot sizesis used to produce one of the at least two sub patterns; projecting theplurality of beams onto a substrate; and providing relative motionbetween the substrate and the plurality of radiation sources, in ascanning direction to expose the substrate.

In an embodiment, the method further comprises decomposing the patternto be produced on the substrate to the at least two sub patterns. In anembodiment, the decomposing comprises decomposing the pattern to the atleast two sub patterns in a manner that the size of the sub pattern tobe produced with the smallest spot size is minimized. In an embodiment,a spot size ratio between at least two of the spot sizes is between 1.2and 5. In an embodiment, the method further comprises creating a controlfile for the plurality of radiation sources producing the same spot sizebased on a transform parameter, a spot parameter, and one of the atleast two sub patterns. In an embodiment, providing the plurality ofbeams of radiation comprises providing the plurality of beams ofradiation according to the control file. In an embodiment, the transformparameter comprises a determined position of physical structures on thesubstrate, the determined position based on real time measurement by ametrology unit during the patterning process. In an embodiment, the spotparameter is determined during calibration of radiation sources beforethe patterning process. In an embodiment, the spot parameter includesone or more selected from: radiation intensity, radiation spot size,radiation beam shape, calibration data, and/or gray scale factor. In anembodiment, the radiation sources producing the smallest spot size ofthe at least two spot sizes are configured to provide beams with thesmallest spot size across the width of the substrate such that ascanning motion could expose substantially the entire width of thesubstrate to beams of the smallest spot size at a same time. In anembodiment, the plurality of radiation sources comprises light-emittingdiodes (LEDs), vertical external cavity surface emitting lasers(VECSELs) or vertical cavity surface emitting lasers (VCSELs). In anembodiment, the projecting the plurality of beams onto the substratecomprises projecting the plurality of beams onto the substrate using anoptical element. In an embodiment, the substrate is aradiation-sensitive substrate. In an embodiment, the method furthercomprises moving the substrate in a scanning direction while theplurality of radiation sources are kept substantially stationary duringa scanning motion to expose the substrate.

In an embodiment, there is provided an exposure apparatus comprising: asubstrate holder constructed to support a substrate; a patterning deviceconfigured to provide a plurality of beams of radiation modulatedaccording to at least two sub patterns of a pattern using a plurality ofradiation sources, the plurality of radiation sources producingradiation beams of at least two spot sizes such that each of theradiation beams having a same spot size of the at least two spot sizesis used to produce one of the at least two sub patterns; a projectionsystem configured to project the plurality of beams onto the substrate;and an actuator configured to provide relative motion between thesubstrate and the plurality of radiation sources, in a scanningdirection to expose the substrate.

In an embodiment, the apparatus further comprises a control systemconfigured to decompose the pattern to be produced on the substrate tothe at least two sub patterns. In an embodiment, the control system isconfigured to decompose the pattern to the at least two sub patterns ina manner that the size of the sub pattern to be produced with thesmallest spot size is minimized. In an embodiment, a spot size ratiobetween at least two of the spot sizes is between 1.2 and 5. In anembodiment, the apparatus comprises a control system configured tocreate a control file for the plurality of radiation sources producingthe same spot size based on a transform parameter, a spot parameter, andone of the at least two sub patterns. In an embodiment, the patterningdevice is configured to provide the plurality of beams of radiationaccording to the control file. In an embodiment, the transform parametercomprises a determined position of physical structures on the substrate,the determined position based on real time measurement by a metrologyunit during the patterning process. In an embodiment, the spot parameteris determined during calibration of radiation sources before thepatterning process. In an embodiment, the spot parameter includes one ormore selected from: radiation intensity, radiation spot size, radiationbeam shape, calibration data, and/or gray scale factor. In anembodiment, the radiation sources producing the smallest spot size ofthe at least two spot sizes are configured to provide beams with thesmallest spot size across the width of the substrate such that ascanning motion could expose substantially the entire width of thesubstrate to beams of the smallest spot size at a same time. In anembodiment, the plurality of radiation sources comprises light-emittingdiodes (LEDs), vertical external cavity surface emitting lasers(VECSELs) or vertical cavity surface emitting lasers (VCSELs). In anembodiment, projecting the plurality of beams onto the substratecomprises projecting the plurality of beams onto the substrate using anoptical element. In an embodiment, the substrate is aradiation-sensitive substrate. In an embodiment, the actuator is furtherconfigured to move the substrate in a scanning direction while theplurality of radiation sources are kept substantially stationary duringa scanning motion to expose the substrate.

In an embodiment, there is provided an exposure apparatus comprising: asubstrate holder constructed to support a substrate; a patterning deviceconfigured to provide radiation modulated according to a desiredpattern, the patterning device comprising a plurality of rows oftwo-dimensional arrays of radiation sources; a projection systemconfigured to project the modulated radiation onto a substrate; and oneor more fluid removal units configured to remove a fluid from betweenthe projection system and the substrate.

In an embodiment, at least two adjacent two-dimensional arrays ofradiation sources are separated by an open space and the one or morefluid removal units are configured to draw fluid through the open spacefrom above, or below, the patterning device to between the projectionsystem and the substrate. In an embodiment, at least one fluid removalunit is situated on top of, or below, the patterning device. In anembodiment, at least one fluid removal unit is situated at side of thepatterning device. In an embodiment, at least one fluid removal unit islocated at a back side of the patterning device relative to a scanningdirection. In an embodiment, the one or more fluid removal units extendacross the width or length of at least one of the rows. In anembodiment, the one or more fluid removal units are configured to removefluid near the one or more fluid removal units to cause a pressure dropand the pressure drop forcing fluid towards the one or more fluidremoval units, the forced fluid passing between the substrate and theprojection system, the forced fluid carrying away contamination betweenthe substrate and the projection system. In an embodiment, a first rowof two-dimensional array of radiation sources and a second row oftwo-dimensional array of radiation sources adjacent to the first row oftwo-dimensional array of radiation sources have a displacement along adirection perpendicular to the scanning direction such that at leastsome of the beams of the first row of two-dimensional array would exposeregions of the substrate that interleave regions of the substrate thatwould be exposed by at least some of the beams of the second row oftwo-dimensional arrays. In an embodiment, the plurality of rows oftwo-dimensional arrays of radiation sources sufficiently extend acrossthe width of the substrate such that a scanning motion can exposesubstantially the entire width of the substrate to the plurality ofbeams at a same time. In an embodiment, the plurality of radiationsources comprises light-emitting diodes (LEDs), vertical external cavitysurface emitting lasers (VECSELs) or vertical cavity surface emittinglasers (VCSELs). In an embodiment, the projection system comprises aplurality of optical elements, the optical elements being microlensesand the plurality of optical elements forming a two-dimensionalmicrolens array. In an embodiment, the substrate is aradiation-sensitive substrate. In an embodiment, the apparatus furthercomprises an actuator configured to provide relative motion between thesubstrate and the plurality of rows of two-dimensional arrays ofradiation sources in a scanning direction to expose the substrate.

In an embodiment, there is provided a device manufacturing methodcomprising: providing radiation modulated according to a desired patternusing a plurality of rows of two-dimensional arrays of radiationsources; projecting the modulated radiation onto a substrate using aprojection system; and removing fluid from between the projection systemand the substrate using one or more fluid removal units.

In an embodiment, at least two adjacent two-dimensional arrays ofradiation sources are separated by an open space and drawing fluidthrough the open space from above, or below, the patterning device tobetween the projection system and the substrate using the one or morefluid removal units. In an embodiment, at least one fluid removal unitis situated on top of, or below, the patterning device. In anembodiment, at least one fluid removal unit is situated at side of thepatterning device. In an embodiment, at least one fluid removal unit islocated at a back side of the patterning device relative to a scanningdirection. In an embodiment, the one or more fluid removal units extendacross the width or length of at least one of the rows. In anembodiment, the method comprises removing fluid near the one or morefluid removal units using the one or more fluid removal units to cause apressure drop and the pressure drop forcing fluid towards the one ormore fluid removal units, the forced fluid passing between the substrateand the projection system, the forced fluid carrying away contaminationbetween the substrate and the projection system. In an embodiment, afirst row of two-dimensional array of radiation sources and a second rowof two-dimensional array of radiation sources adjacent to the first rowof two-dimensional array of radiation sources have a displacement alonga direction perpendicular to the scanning direction such that at leastsome of the beams of the first row of two-dimensional array would exposeregions of the substrate that interleave regions of the substrate thatwould be exposed by at least some of the beams of the second row oftwo-dimensional arrays. In an embodiment, the plurality of rows oftwo-dimensional arrays of radiation sources sufficiently extend acrossthe width of the substrate such that a scanning motion can exposesubstantially the entire width of the substrate to the plurality ofbeams at a same time. In an embodiment, the plurality of radiationsources comprises light-emitting diodes (LEDs), vertical external cavitysurface emitting lasers (VECSELs) or vertical cavity surface emittinglasers (VCSELs). In an embodiment, the projection system comprises aplurality of optical elements, the optical elements being microlensesand the plurality of optical elements forming a two-dimensionalmicrolens array. In an embodiment, the substrate is aradiation-sensitive substrate. In an embodiment, the method furthercomprises providing relative motion between the substrate and theplurality of rows of two-dimensional arrays of radiation sources in ascanning direction to expose the substrate. In an embodiment, the fluidcomprises contamination.

Although specific reference may be made in this text to the use of alithographic apparatus in the manufacture of a specific device orstructure (e.g. an integrated circuit or a flat panel display), itshould be understood that the lithographic apparatus and lithographicmethod described herein may have other applications. Applicationsinclude, but are not limited to, the manufacture of integrated circuits,integrated optical systems, guidance and detection patterns for magneticdomain memories, flat panel displays, LCDs, OLED displays, thin filmmagnetic heads, micro-electromechanical devices (MEMS),micro-opto-electromechanical systems (MOEMS), DNA chips, packaging(e.g., flip chip, redistribution, etc.), flexible displays orelectronics (which are displays or electronics that may be rollable,bendable like paper and remain free of deformities, conformable, rugged,thin, and/or lightweight, e.g., flexible plastic displays), etc. Also,for instance in a flat panel display, the present apparatus and methodmay be used to assist in the creation of a variety of layers, e.g. athin film transistor layer and/or a color filter layer. Thus, avariation of the same apparatus herein could be used in the manufactureof various electronic and other devices or patterns, including, e.g., onflexible substrates, such as plastic or metal foil using e.g.roll-to-roll techniques and/or foil on a glass carrier.

The skilled artisan will appreciate that, in the context of suchalternative applications, any use of the terms “wafer” or “die” hereinmay be considered as synonymous with the more general terms “substrate”or “target portion,” respectively. The substrate referred to herein maybe processed, before or after exposure, in for example a track (e.g., atool that typically applies a layer of resist to a substrate anddevelops the exposed resist) or a metrology or inspection tool. Whereapplicable, the disclosure herein may be applied to such and othersubstrate processing tools. Further, the substrate may be processed morethan once, for example in order to create a multi-layer IC, so that theterm substrate used herein may also refer to a substrate that alreadycontains multiple processed layers.

A flat panel display substrate may be rectangular in shape. Alithographic apparatus designed to expose a substrate of this type mayprovide an exposure region which covers a full width of the rectangularsubstrate, or which covers a portion of the width (for example half ofthe width). The substrate may be scanned underneath the exposure region,while the patterning device synchronously provides the patterned beam.In this way, all or part of the desired pattern is transferred to thesubstrate. If the exposure region covers the full width of the substratethen exposure may be completed with a single scan. If the exposureregion covers, for example, half of the width of the substrate, then thesubstrate may be moved transversely after the first scan, and a furtherscan is typically performed to expose the remainder of the substrate.

The term “patterning device”, used herein should be broadly interpretedas referring to any device that can be used to modulate thecross-section of a radiation beam such as to create a pattern in (partof) the substrate. It should be noted that the pattern imparted to theradiation beam may not exactly correspond to the desired pattern in thetarget portion of the substrate, for example if the pattern includesphase-shifting features or so called assist features. Similarly, thepattern eventually generated on the substrate may not correspond to thepattern formed at any one instant by the array of individuallyaddressable elements. This may be the case in an arrangement in whichthe eventual pattern formed on each part of the substrate is built upover a given period of time or a given number of exposures during whichthe pattern provided by the array of individually addressable elementsand/or the relative position of the substrate changes. Generally, thepattern created on the target portion of the substrate will correspondto a particular functional layer in a device being created in the targetportion, e.g., an integrated circuit or a flat panel display (e.g., acolor filter layer in a flat panel display or a thin film transistorlayer in a flat panel display). Examples of such patterning devicesinclude, e.g., reticles, programmable mirror arrays, laser diode arrays,light emitting diode arrays, grating light valves, and LCD arrays.Patterning devices whose pattern is programmable with the aid of anelectronic devices (e.g., a computer), e.g., patterning devicescomprising a plurality of programmable elements that can each modulatethe intensity of a portion of the radiation beam, (e.g., all the devicesmentioned in the previous sentence except for the reticle), includingelectronically programmable patterning devices having a plurality ofprogrammable elements that impart a pattern to the radiation beam bymodulating the phase of a portion of the radiation beam relative toadjacent portions of the radiation beam, are collectively referred toherein as “contrast devices”. In an embodiment, the patterning devicecomprises at least 10 programmable elements, e.g. at least 100, at least1000, at least 10000, at least 100000, at least 1000000, or at least10000000 programmable elements. Embodiments of several of these devicesare discussed in some more detail below:

-   -   A programmable mirror array. The programmable mirror array may        comprise a matrix-addressable surface having a viscoelastic        control layer and a reflective surface. The basic principle        behind such an apparatus is that, for example, addressed areas        of the reflective surface reflect incident radiation as        diffracted radiation, whereas unaddressed areas reflect incident        radiation as undiffracted radiation. Using an appropriate        spatial filter, the undiffracted radiation can be filtered out        of the reflected beam, leaving only the diffracted radiation to        reach the substrate. In this manner, the beam becomes patterned        according to the addressing pattern of the matrix-addressable        surface. As an alternative, the filter may filter out the        diffracted radiation, leaving the undiffracted radiation to        reach the substrate. An array of diffractive optical MEMS        devices may also be used in a corresponding manner. A        diffractive optical MEMS device may comprise a plurality of        reflective ribbons that may be deformed relative to one another        to form a grating that reflects incident radiation as diffracted        radiation. A further embodiment of a programmable mirror array        employs a matrix arrangement of tiny mirrors, each of which may        be individually tilted about an axis by applying a suitable        localized electric field, or by employing piezoelectric        actuation means. The degree of tilt defines the state of each        mirror. The mirrors are controllable, when the element is not        defective, by appropriate control signals from the controller.        Each non-defective element is controllable to adopt any one of a        series of states, so as to adjust the intensity of its        corresponding pixel in the projected radiation pattern. Once        again, the mirrors are matrix-addressable, such that addressed        mirrors reflect an incoming radiation beam in a different        direction to unaddressed mirrors; in this manner, the reflected        beam may be patterned according to the addressing pattern of the        matrix-addressable mirrors. The required matrix addressing may        be performed using suitable electronic means. More information        on mirror arrays as here referred to can be gleaned, for        example, from U.S. Pat. Nos. 5,296,891 and 5,523,193, and PCT        Patent Application Publication Nos. WO 98/38597 and WO 98/33096,        which are incorporated herein by reference in their entirety.    -   A programmable LCD array. An example of such a construction is        given in U.S. Pat. No. 5,229,872, which is incorporated herein        by reference in its entirety.

The lithographic apparatus may comprise one or more patterning devices,e.g. one or more contrast devices. For example, it may have a pluralityof arrays of individually addressable elements, each controlledindependently of each other. In such an arrangement, some or all of thearrays of individually addressable elements may have at least one of acommon illumination system (or part of an illumination system), a commonsupport structure for the arrays of individually addressable elementsand/or a common projection system (or part of the projection system).

Where pre-biasing of features, optical proximity correction features,phase variation techniques and/or multiple exposure techniques are used,for example, the pattern “displayed” on the array of individuallyaddressable elements may differ substantially from the patterneventually transferred to a layer of or on the substrate. Similarly, thepattern eventually generated on the substrate may not correspond to thepattern formed at any one instant on the array of individuallyaddressable elements. This may be the case in an arrangement in whichthe eventual pattern formed on each part of the substrate is built upover a given period of time or a given number of exposures during whichthe pattern on the array of individually addressable elements and/or therelative position of the substrate changes.

The projection system and/or illumination system may include varioustypes of optical components, e.g., refractive, reflective, magnetic,electromagnetic, electrostatic or other types of optical components, orany combination thereof, to direct, shape, or control the beam ofradiation.

The lithographic apparatus may be of a type having two (e.g., dualstage) or more substrate tables (and/or two or more patterning devicetables) or one or more substrate tables in combination with anothertable not holding a substrate (e.g., a table for cleaning, and/ormeasurement, etc.). In such “multiple stage” machines the additionaltable(s) may be used in parallel, or preparatory steps may be carriedout on one or more tables while one or more other tables are being usedfor exposure.

The lithographic apparatus may also be of a type wherein at least aportion of the substrate may be covered by an “immersion liquid” havinga relatively high refractive index, e.g. water, so as to fill a spacebetween the projection system and the substrate. An immersion liquid mayalso be applied to other spaces in the lithographic apparatus, forexample, between the patterning device and the projection system.Immersion techniques are used to increase the NA of projection system.The term “immersion” as used herein does not mean that a structure,e.g., a substrate, must be submerged in liquid, but rather only meansthat liquid is located between the projection system and the substrateduring exposure.

Further, the apparatus may be provided with a fluid processing cell toallow interactions between a fluid and irradiated parts of the substrate(e.g., to selectively attach chemicals to the substrate or toselectively modify the surface structure of the substrate).

In an embodiment, the substrate has a substantially circular shape,optionally with a notch and/or a flattened edge along part of itsperimeter. In an embodiment, the substrate has a polygonal shape, e.g. arectangular shape. Embodiments where the substrate has a substantiallycircular shape include embodiments where the substrate has a diameter ofat least 25 mm, for instance at least 50 mm, at least 75 mm, at least100 mm, at least 125 mm, at least 150 mm, at least 175 mm, at least 200mm, at least 250 mm, or at least 300 mm. In an embodiment, the substratehas a diameter of at most 500 mm, at most 400 mm, at most 350 mm, atmost 300 mm, at most 250 mm, at most 200 mm, at most 150 mm, at most 100mm, or at most 75 mm. Embodiments where the substrate is polygonal, e.g.rectangular, include embodiments where at least one side, e.g. at least2 sides or at least 3 sides, of the substrate has a length of at least 5cm, e.g. at least 25 cm, at least 50 cm, at least 100 cm, at least 150cm, at least 200 cm, or at least 250 cm. In an embodiment, at least oneside of the substrate has a length of at most 1000 cm, e.g. at most 750cm, at most 500 cm, at most 350 cm, at most 250 cm, at most 150 cm, orat most 75 cm. In an embodiment, the substrate is a rectangularsubstrate having a length of about 250-350 cm and a width of about250-300 cm The thickness of the substrate may vary and, to an extent,may depend, e.g., on the substrate material and/or the substratedimensions. In an embodiment, the thickness is at least 50 μm, forinstance at least 100 μm, at least 200 μm, at least 300 μm, at least 400μm, at least 500 μm, or at least 600 μm. In one embodiment, thethickness of the substrate is at most 5000 μm, for instance at most 3500μm, at most 2500 μm, at most 1750 μm, at most 1250 μm, at most 1000 μm,at most 800 μm, at most 600 μm, at most 500 μm, at most 400 μm, or atmost 300 μm. The substrate referred to herein may be processed, beforeor after exposure, in for example a track (a tool that typically appliesa layer of resist to a substrate and develops the exposed resist).Properties of the substrate may be measured before or after exposure,for example in a metrology tool and/or an inspection tool.

In an embodiment, a resist layer is provided on the substrate. In anembodiment, the substrate is a wafer, for instance a semiconductorwafer. In an embodiment, the wafer material is selected from the groupconsisting of Si, SiGe, SiGeC, SiC, Ge, GaAs, InP, and InAs. In anembodiment, the wafer is a III/V compound semiconductor wafer. In anembodiment, the wafer is a silicon wafer. In an embodiment, thesubstrate is a ceramic substrate. In an embodiment, the substrate is aglass substrate. Glass substrates may be useful, e.g., in themanufacture of flat panel displays and liquid crystal display panels. Inan embodiment, the substrate is a plastic substrate. In an embodiment,the substrate is transparent (for the naked human eye). In anembodiment, the substrate is colored. In an embodiment, the substrate isabsent a color. In an embodiment, the substrate comprises a plastic foilon temporary glass carrier. This can include a coated layer of e.g.polyimide on a glass substrate, which is processed in similar fashion toa glass display, but where the glass is removed after processing using,e.g., a UV laser step, desirably after laminating the remaining foilwith a protective plastic foil for increased robustness and ease ofhandling.

While, in an embodiment, the patterning device 104 is described and/ordepicted as being above the substrate 114, it may instead oradditionally be located under the substrate 114. Further, in anembodiment, the patterning device 104 and the substrate 114 may be sideby side, e.g., the patterning device 104 and substrate 114 extendvertically and the pattern is projected horizontally. In an embodiment,a patterning device 104 is provided to expose at least two oppositesides of a substrate 114. For example, there may be at least twopatterning devices 104, at least on each respective opposing side of thesubstrate 114, to expose those sides. In an embodiment, there may be asingle patterning device 104 to project one side of the substrate 114and appropriate optics (e.g., beam directing mirrors) to project apattern from the single patterning device 104 onto another side of thesubstrate 114.

In the description herein, the term “lens” should be understoodgenerally to encompass any refractive, reflective, and/or diffractiveoptical element that provides the same function as the referenced lens.For example, an imaging lens may be embodied in the form of aconventional refractive lens having optical power, in the form of aSchwarzschild reflective system having optical power, and/or in the formof a zone plate having optical power. Moreover, an imaging lens maycomprise non-imaging optics if the resulting effect is to produce aconverged beam.

While specific embodiments have been described above, it will beappreciated that the invention may be practiced otherwise than asdescribed. For example, an embodiment of the invention may take the formof a computer program containing one or more sequences ofmachine-readable instructions describing a method as disclosed above, ora data storage medium (e.g. semiconductor memory, magnetic or opticaldisk) having such a computer program stored therein.

Moreover, although certain embodiments and examples have been described,it will be understood by those skilled in the art that the presentinvention extends beyond the specifically disclosed embodiments to otheralternative embodiments and/or uses of the invention and obviousmodifications and equivalents thereof. In addition, while a number ofvariations of the invention have been shown and described in detail,other modifications, which are within the scope of this invention, willbe readily apparent to those of skill in the art based upon thisdisclosure. For example, it is contemplated that various combination orsub-combinations of the specific features and aspects of the embodimentsmay be made and still fall within the scope of the invention.Accordingly, it should be understood that various features and aspectsof the disclosed embodiments can be combined with or substituted for oneanother in order to form varying modes of the disclosed invention. In anembodiment, one or more features or aspects disclosed in U.S. patentapplication publication no. US 2011-0188016 and PCT patent applicationpublication no. WO 2010/032224, the entire contents of U.S. patentapplication publication no. US 2011-0188016 and PCT patent applicationpublication no. WO 2010/032224 incorporated herein by reference, may becombined with or substituted for one or more features or aspectsdisclosed herein.

The invention may further be described using the following clauses:

-   1. A device manufacturing method comprising:

providing a plurality of beams of radiation modulated according to atleast two sub patterns of a pattern using a plurality of radiationsources, the plurality of radiation sources producing radiation beams ofat least two spot sizes such that each of the radiation beams having asame spot size of the at least two spot sizes is used to produce one ofthe at least two sub patterns;

projecting the plurality of beams onto a substrate; and

providing relative motion between the substrate and the plurality ofradiation sources, in a scanning direction to expose the substrate.

-   2. The method of clause 1, further comprising decomposing the    pattern to be produced on the substrate to the at least two sub    patterns.-   3. The method of clause 2, wherein the decomposing comprises    decomposing the pattern to the at least two sub patterns in a manner    that the size of the sub pattern to be produced with the smallest    spot size is minimized.-   4. The method of any of clauses 1 to 3, wherein a spot size ratio    between at least two of the spot sizes is between 1.2 and 5.-   5. The method of any of clauses 1 to 3, further comprising creating    a control file for the plurality of radiation sources producing the    same spot size based on a transform parameter, a spot parameter, and    one of the at least two sub patterns.-   6. The method of clause 5, wherein providing the plurality of beams    of radiation comprises providing the plurality of beams of radiation    according to the control file.-   7. The method of clause 5 or clause 6, wherein the transform    parameter comprises a determined position of physical structures on    the substrate, the determined position based on real time    measurement by a metrology unit during the patterning process.-   8. The method of any of clauses 5 to 7, wherein the spot parameter    is determined during calibration of radiation sources before the    patterning process.-   9. The method of any of clauses 5 to 9, wherein the spot parameter    includes one or more selected from: radiation intensity, radiation    spot size, radiation beam shape, calibration data, and/or gray scale    factor.-   10. The method of any of clauses 1 to 9, wherein the radiation    sources producing the smallest spot size of the at least two spot    sizes are configured to provide beams with the smallest spot size    across the width of the substrate such that a scanning motion could    expose substantially the entire width of the substrate to beams of    the smallest spot size at a same time.-   11. The method of any of clauses 1 to 10, wherein the plurality of    radiation sources comprises light-emitting diodes (LEDs), vertical    external cavity surface emitting lasers (VECSELs) or vertical cavity    surface emitting lasers (VCSELs).-   12. The method of any of clauses 1 to 11, wherein the projecting the    plurality of beams onto the substrate comprises projecting the    plurality of beams onto the substrate using an optical element.-   13. The method of any of clauses 1 to 12, wherein the substrate is a    radiation-sensitive substrate.-   14. The method of any of clauses 1 to 13, further comprising moving    the substrate in a scanning direction while the plurality of    radiation sources are kept substantially stationary during a    scanning motion to expose the substrate.-   15. An exposure apparatus comprising:

a substrate holder constructed to support a substrate;

a patterning device configured to provide a plurality of beams ofradiation modulated according to at least two sub patterns of a patternusing a plurality of radiation sources, the plurality of radiationsources producing radiation beams of at least two spot sizes such thateach of the radiation beams having a same spot size of the at least twospot sizes is used to produce one of the at least two sub patterns;

a projection system configured to project the plurality of beams ontothe substrate; and

an actuator configured to provide relative motion between the substrateand the plurality of radiation sources, in a scanning direction toexpose the substrate.

-   16. The apparatus of clause 15, further comprising a control system    configured to decompose the pattern to be produced on the substrate    to the at least two sub patterns.-   17. The apparatus of clause 16, wherein the control system is    configured to decompose the pattern to the at least two sub patterns    in a manner that the size of the sub pattern to be produced with the    smallest spot size is minimized.-   18. The apparatus of any of clauses 15 to 17, wherein a spot size    ratio between at least two of the spot sizes is between 1.2 and 5.-   19. The apparatus of any of clauses 15 to 18, comprising a control    system configured to create a control file for the plurality of    radiation sources producing the same spot size based on a transform    parameter, a spot parameter, and one of the at least two sub    patterns.-   20. The apparatus of clause 19, wherein the patterning device is    configured to provide the plurality of beams of radiation according    to the control file.-   21. The apparatus of clause 19 or clause 20, wherein the transform    parameter comprises a determined position of physical structures on    the substrate, the determined position based on real time    measurement by a metrology unit during the patterning process.-   22. The apparatus of any of clauses 19 to 21, wherein the spot    parameter is determined during calibration of radiation sources    before the patterning process.-   23. The apparatus of any of clauses 19 to 22, wherein the spot    parameter includes one or more selected from: radiation intensity,    radiation spot size, radiation beam shape, calibration data, and/or    gray scale factor.-   24. The apparatus of any of clauses 15 to 23, wherein the radiation    sources producing the smallest spot size of the at least two spot    sizes are configured to provide beams with the smallest spot size    across the width of the substrate such that a scanning motion could    expose substantially the entire width of the substrate to beams of    the smallest spot size at a same time.-   25. The apparatus of any of clauses 15 to 24, wherein the plurality    of radiation sources comprises light-emitting diodes (LEDs),    vertical external cavity surface emitting lasers (VECSELs) or    vertical cavity surface emitting lasers (VCSELs).-   26. The apparatus of any of clauses 15 to 25, wherein projecting the    plurality of beams onto the substrate comprises projecting the    plurality of beams onto the substrate using an optical element.-   27. The apparatus of any of clauses 15 to 26, wherein the substrate    is a radiation-sensitive substrate.-   28. The apparatus of any of clauses 15 to 27, wherein the actuator    is further configured to move the substrate in a scanning direction    while the plurality of radiation sources are kept substantially    stationary during a scanning motion to expose the substrate.-   29. An exposure apparatus comprising:

a substrate holder constructed to support a substrate;

a patterning device configured to provide radiation modulated accordingto a desired pattern, the patterning device comprising a plurality ofrows of two-dimensional arrays of radiation sources;

a projection system configured to project the modulated radiation onto asubstrate; and

one or more fluid removal units configured to remove a fluid frombetween the projection system and the substrate.

-   30. The apparatus of clause 29, wherein at least two adjacent    two-dimensional arrays of radiation sources are separated by an open    space and the one or more fluid removal units are configured to draw    fluid through the open space from above, or below, the patterning    device to between the projection system and the substrate.-   31. The apparatus of clause 29 or clause 30, wherein at least one    fluid removal unit is situated on top of, or below, the patterning    device.-   32. The apparatus of any of clauses 29 to 31, wherein at least one    fluid removal unit is situated at side of the patterning device.-   33. The apparatus of clause 32, wherein at least one fluid removal    unit is located at a back side of the patterning device relative to    a scanning direction.-   34. The apparatus of any of clauses 29 to 33, wherein the one or    more fluid removal units extend across the width or length of at    least one of the rows.-   35. The apparatus of any of clauses 29 to 34, wherein the one or    more fluid removal units are configured to remove fluid near the one    or more fluid removal units to cause a pressure drop and the    pressure drop forcing fluid towards the one or more fluid removal    units, the forced fluid passing between the substrate and the    projection system, the forced fluid carrying away contamination    between the substrate and the projection system.-   36. The apparatus of any of clauses 29 to 35, wherein a first row of    two-dimensional array of radiation sources and a second row of    two-dimensional array of radiation sources adjacent to the first row    of two-dimensional array of radiation sources have a displacement    along a direction perpendicular to the scanning direction such that    at least some of the beams of the first row of two-dimensional array    would expose regions of the substrate that interleave regions of the    substrate that would be exposed by at least some of the beams of the    second row of two-dimensional arrays.-   37. The apparatus of any of clauses 29 to 36, wherein the plurality    of rows of two-dimensional arrays of radiation sources sufficiently    extend across the width of the substrate such that a scanning motion    can expose substantially the entire width of the substrate to the    plurality of beams at a same time.-   38. The apparatus of any of clauses 29 to 37, wherein the plurality    of radiation sources comprises light-emitting diodes (LEDs),    vertical external cavity surface emitting lasers (VECSELs) or    vertical cavity surface emitting lasers (VCSELs).-   39. The apparatus of any of clauses 29 to 38, wherein the projection    system comprises a plurality of optical elements, the optical    elements being microlenses and the plurality of optical elements    forming a two-dimensional microlens array.-   40. The apparatus of any of clauses 29 to 39, wherein the substrate    is a radiation-sensitive substrate.-   41. The apparatus of any of clauses 29 to 40, further comprising an    actuator configured to provide relative motion between the substrate    and the plurality of rows of two-dimensional arrays of radiation    sources in a scanning direction to expose the substrate.-   42. A device manufacturing method comprising:

providing radiation modulated according to a desired pattern using aplurality of rows of two-dimensional arrays of radiation sources;

projecting the modulated radiation onto a substrate using a projectionsystem; and

removing fluid from between the projection system and the substrateusing one or more fluid removal units.

-   43. The method of clause 42, wherein at least two adjacent    two-dimensional arrays of radiation sources are separated by an open    space and drawing fluid through the open space from above, or below,    the patterning device to between the projection system and the    substrate using the one or more fluid removal units.-   44. The method of clause 42 or clause 43, wherein at least one fluid    removal unit is situated on top of, or below, the patterning device.-   45. The method of any of clauses 42 to 44, wherein at least one    fluid removal unit is situated at side of the patterning device.-   46. The method of clause 45, wherein at least one fluid removal unit    is located at a back side of the patterning device relative to a    scanning direction.-   47. The method of any of clauses 42 to 46, wherein the one or more    fluid removal units extend across the width or length of at least    one of the rows.-   48. The method of any of clauses 42 to 47, comprising removing fluid    near the one or more fluid removal units using the one or more fluid    removal units to cause a pressure drop and the pressure drop forcing    fluid towards the one or more fluid removal units, the forced fluid    passing between the substrate and the projection system, the forced    fluid carrying away contamination between the substrate and the    projection system.-   49. The method of any of clauses 42 to 48, wherein a first row of    two-dimensional array of radiation sources and a second row of    two-dimensional array of radiation sources adjacent to the first row    of two-dimensional array of radiation sources have a displacement    along a direction perpendicular to the scanning direction such that    at least some of the beams of the first row of two-dimensional array    would expose regions of the substrate that interleave regions of the    substrate that would be exposed by at least some of the beams of the    second row of two-dimensional arrays.-   50. The method of any of clauses 42 to 49, wherein the plurality of    rows of two-dimensional arrays of radiation sources sufficiently    extend across the width of the substrate such that a scanning motion    can expose substantially the entire width of the substrate to the    plurality of beams at a same time.-   51. The method of any of clauses 42 to 50, wherein the plurality of    radiation sources comprises light-emitting diodes (LEDs), vertical    external cavity surface emitting lasers (VECSELs) or vertical cavity    surface emitting lasers (VCSELs).-   52. The method of any of clauses 42 to 51, wherein the projection    system comprises a plurality of optical elements, the optical    elements being microlenses and the plurality of optical elements    forming a two-dimensional microlens array.-   53. The method of any of clauses 42 to 52, wherein the substrate is    a radiation-sensitive substrate.-   54. The method of any of clauses 42 to 53, further comprising    providing relative motion between the substrate and the plurality of    rows of two-dimensional arrays of radiation sources in a scanning    direction to expose the substrate.-   55. The method of any of clauses 42 to 54, wherein the fluid    comprises contamination.-   56. Use of the method of any of clauses 1 to 14 or clauses 42 to 55    or the apparatus of any of clauses 15 to 41 in the manufacture of    flat panel displays.-   57. Use of the method of any of clauses 1 to 14 or clauses 42 to 55    or the apparatus of any of clauses 15 to 41 in the manufacture of    integrated circuits.-   58. A flat panel display manufactured using the method of any of    clauses 1 to 14 or clauses 42 to 55 or the apparatus of any of    clauses 15 to 41.-   59. An integrated circuit device manufactured using the method of    any of clauses 1 to 14 or clauses 42 to 55 or the apparatus of any    of clauses 15 to 41.

Thus, while various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. It will be apparent to persons skilled in the relevant artthat various changes in form and detail can be made therein withoutdeparting from the spirit and scope of the invention. Thus, the breadthand scope of the present invention should not be limited by any of theabove-described exemplary embodiments, but should be defined only inaccordance with the following claims and their equivalents.

What is claimed is:
 1. An exposure apparatus comprising: a substrateholder constructed to support a substrate; a patterning deviceconfigured to provide a plurality of beams of radiation modulatedaccording to at least two sub patterns of a pattern using a plurality ofradiation sources, the plurality of radiation sources producingradiation beams of at least two spot sizes such that each of theradiation beams having a same spot size of the at least two spot sizesis used to produce one of the at least two sub patterns; a projectionsystem configured to project the plurality of beams onto the substrate;an actuator configured to provide relative motion between the substrateand the plurality of radiation sources, in a scanning direction toexpose the substrate; and a control system configured to cause theradiation beams of the at least two spot sizes to expose the samesubstrate during relative motion between the substrate and the pluralityof radiation sources.
 2. The apparatus of claim 1, wherein the controlsystem is further configured to decompose the pattern to be produced onthe substrate to the at least two sub patterns.
 3. The apparatus ofclaim 2, wherein the control system is configured to decompose thepattern to the at least two sub patterns in a manner that the size ofthe sub pattern to be produced with the smallest spot size is minimized.4. The apparatus of claim 1, wherein a spot size ratio between at leasttwo of the spot sizes is between 1.2 and
 5. 5. The apparatus of claim 1,wherein the control system is further configured to create a controlfile for the plurality of radiation sources producing the same spot sizebased on a transform parameter, a spot parameter, and one of the atleast two sub patterns.
 6. The apparatus of claim 5, wherein thepatterning device is configured to provide the plurality of beams ofradiation according to the control file.
 7. The apparatus of claim 5,wherein the transform parameter comprises a determined position ofphysical structures on the substrate, the determined position based onreal time measurement by a metrology unit during a patterning process.8. The apparatus of claim 5, wherein the spot parameter is determinedduring calibration of radiation sources before a patterning process. 9.The apparatus of claim 5, wherein the spot parameter includes one ormore selected from: radiation intensity, radiation spot size, radiationbeam shape, calibration data, and/or gray scale factor.
 10. Theapparatus of claim 1, wherein the radiation sources producing thesmallest spot size of the at least two spot sizes are configured toprovide beams with the smallest spot size across the width of thesubstrate such that a scanning motion could expose substantially theentire width of the substrate to beams of the smallest spot size at asame time.
 11. The apparatus of claim 1, wherein the plurality ofradiation sources comprises light-emitting diodes (LEDs), verticalexternal cavity surface emitting lasers (VECSELs) or vertical cavitysurface emitting lasers (VCSELs).
 12. The apparatus of claim 1, whereinthe actuator is further configured to move the substrate in a scanningdirection while the plurality of radiation sources are keptsubstantially stationary during a scanning motion to expose thesubstrate.
 13. A device manufacturing method comprising: providing aplurality of beams of radiation modulated according to at least two subpatterns of a pattern using a plurality of radiation sources of anexposure apparatus, the plurality of radiation sources producingradiation beams of at least two spot sizes such that each of theradiation beams having a same spot size of the at least two spot sizesis used to produce one of the at least two sub patterns; projecting theplurality of beams of the at least two spot sizes onto a same substrate;and providing relative motion between the substrate and the plurality ofradiation sources, in a scanning direction to expose the substrate. 14.A non-transitory computer program product comprising machine-readableinstructions configured to cause, upon execution by a processing system,the processing system to at least: determine a plurality of beams ofradiation to be modulated according to at least two sub patterns of apattern using a plurality of radiation sources of an exposure apparatus,the plurality of radiation sources producing radiation beams of at leasttwo spot sizes such that each of the radiation beams having a same spotsize of the at least two spot sizes is used to produce one of the atleast two sub patterns; and provide an electronic signal to enableprojecting of the plurality of beams of radiation modulated according tothe at least two sub patterns onto a same substrate while relativemotion is provided between the substrate and the plurality of radiationsources, in a scanning direction to expose the substrate with theplurality of beams.
 15. The computer program product claim 14, whereinthe instructions are further configured to cause the processing systemto decompose the pattern to be produced on the substrate to the at leasttwo sub patterns.
 16. The computer program product of claim 15, whereinthe instructions are further configured to cause the processing systemto decompose the pattern to the at least two sub patterns in a mannerthat the size of the sub pattern to be produced with the smallest spotsize is minimized.
 17. The computer program product of claim 14, whereina spot size ratio between at least two of the spot sizes is between 1.2and
 5. 18. The computer program product of claim 14, wherein theinstructions are further configured to cause the processing system tocreate a control file for the plurality of radiation sources producingthe same spot size based on a transform parameter, a spot parameter, andone of the at least two sub patterns.
 19. The computer program productof claim 14, wherein the transform parameter comprises a determinedposition of physical structures on the substrate, the determinedposition based on real time measurement by a metrology unit during apatterning process.
 20. The computer program product of claim 14,wherein the spot parameter is determined during calibration of radiationsources before a patterning process.